diff --git a/app/containers/ActionSheet/Button.ts b/app/containers/ActionSheet/Button.ts
index 5deb0f692..186cc6851 100644
--- a/app/containers/ActionSheet/Button.ts
+++ b/app/containers/ActionSheet/Button.ts
@@ -1,7 +1,8 @@
+import React from 'react';
 import { TouchableOpacity } from 'react-native';
 
 import { isAndroid } from '../../utils/deviceInfo';
 import Touch from '../../utils/touch';
 
 // Taken from https://github.com/rgommezz/react-native-scroll-bottom-sheet#touchables
-export const Button = isAndroid ? Touch : TouchableOpacity;
+export const Button: typeof React.Component = isAndroid ? Touch : TouchableOpacity;
diff --git a/app/containers/Avatar/Avatar.tsx b/app/containers/Avatar/Avatar.tsx
index 286bcc060..0ad2634f2 100644
--- a/app/containers/Avatar/Avatar.tsx
+++ b/app/containers/Avatar/Avatar.tsx
@@ -5,6 +5,7 @@ import Touchable from 'react-native-platform-touchable';
 import { settings as RocketChatSettings } from '@rocket.chat/sdk';
 
 import { avatarURL } from '../../utils/avatar';
+import { SubscriptionType } from '../../definitions/ISubscription';
 import Emoji from '../markdown/Emoji';
 import { IAvatar } from './interfaces';
 
@@ -27,8 +28,8 @@ const Avatar = React.memo(
 		text,
 		size = 25,
 		borderRadius = 4,
-		type = 'd'
-	}: Partial<IAvatar>) => {
+		type = SubscriptionType.DIRECT
+	}: IAvatar) => {
 		if ((!text && !avatar && !emoji && !rid) || !server) {
 			return null;
 		}
diff --git a/app/containers/Avatar/index.tsx b/app/containers/Avatar/index.tsx
index 9c95db839..2ce066479 100644
--- a/app/containers/Avatar/index.tsx
+++ b/app/containers/Avatar/index.tsx
@@ -7,17 +7,17 @@ import { getUserSelector } from '../../selectors/login';
 import Avatar from './Avatar';
 import { IAvatar } from './interfaces';
 
-class AvatarContainer extends React.Component<Partial<IAvatar>, any> {
+class AvatarContainer extends React.Component<IAvatar, any> {
 	private mounted: boolean;
 
-	private subscription!: any;
+	private subscription: any;
 
 	static defaultProps = {
 		text: '',
 		type: 'd'
 	};
 
-	constructor(props: Partial<IAvatar>) {
+	constructor(props: IAvatar) {
 		super(props);
 		this.mounted = false;
 		this.state = { avatarETag: '' };
@@ -55,7 +55,7 @@ class AvatarContainer extends React.Component<Partial<IAvatar>, any> {
 		try {
 			if (this.isDirect) {
 				const { text } = this.props;
-				const [user] = await usersCollection.query(Q.where('username', text!)).fetch();
+				const [user] = await usersCollection.query(Q.where('username', text)).fetch();
 				record = user;
 			} else {
 				const { rid } = this.props;
@@ -82,7 +82,7 @@ class AvatarContainer extends React.Component<Partial<IAvatar>, any> {
 	render() {
 		const { avatarETag } = this.state;
 		const { serverVersion } = this.props;
-		return <Avatar avatarETag={avatarETag} serverVersion={serverVersion} {...this.props} />;
+		return <Avatar {...this.props} avatarETag={avatarETag} serverVersion={serverVersion} />;
 	}
 }
 
diff --git a/app/containers/Avatar/interfaces.ts b/app/containers/Avatar/interfaces.ts
index ed7fd3b9e..78152e522 100644
--- a/app/containers/Avatar/interfaces.ts
+++ b/app/containers/Avatar/interfaces.ts
@@ -1,23 +1,23 @@
 export interface IAvatar {
-	server: string;
-	style: any;
+	server?: string;
+	style?: any;
 	text: string;
-	avatar: string;
-	emoji: string;
-	size: number;
-	borderRadius: number;
-	type: string;
-	children: JSX.Element;
-	user: {
-		id: string;
-		token: string;
+	avatar?: string;
+	emoji?: string;
+	size?: number;
+	borderRadius?: number;
+	type?: string;
+	children?: JSX.Element;
+	user?: {
+		id?: string;
+		token?: string;
 	};
-	theme: string;
-	onPress(): void;
-	getCustomEmoji(): any;
-	avatarETag: string;
-	isStatic: boolean | string;
-	rid: string;
-	blockUnauthenticatedAccess: boolean;
-	serverVersion: string;
+	theme?: string;
+	onPress?: () => void;
+	getCustomEmoji?: () => any;
+	avatarETag?: string;
+	isStatic?: boolean | string;
+	rid?: string;
+	blockUnauthenticatedAccess?: boolean;
+	serverVersion?: string;
 }
diff --git a/app/containers/MessageActions/index.tsx b/app/containers/MessageActions/index.tsx
index eb9be9675..4d32abf3b 100644
--- a/app/containers/MessageActions/index.tsx
+++ b/app/containers/MessageActions/index.tsx
@@ -305,8 +305,6 @@ const MessageActions = React.memo(
 			};
 
 			const handleDelete = (message: any) => {
-				// TODO - migrate this function for ts when fix the lint erros
-				// @ts-ignore
 				showConfirmationAlert({
 					message: I18n.t('You_will_not_be_able_to_recover_this_message'),
 					confirmationText: I18n.t('Delete'),
diff --git a/app/containers/Passcode/Base/Button.tsx b/app/containers/Passcode/Base/Button.tsx
index f7e6c1a9a..50a1cf417 100644
--- a/app/containers/Passcode/Base/Button.tsx
+++ b/app/containers/Passcode/Base/Button.tsx
@@ -7,28 +7,28 @@ import Touch from '../../../utils/touch';
 import { CustomIcon } from '../../../lib/Icons';
 
 interface IPasscodeButton {
-	text: string;
-	icon: string;
+	text?: string;
+	icon?: string;
 	theme: string;
-	disabled: boolean;
-	onPress: Function;
+	disabled?: boolean;
+	onPress?: Function;
 }
 
-const Button = React.memo(({ text, disabled, theme, onPress, icon }: Partial<IPasscodeButton>) => {
-	const press = () => onPress && onPress(text!);
+const Button = React.memo(({ text, disabled, theme, onPress, icon }: IPasscodeButton) => {
+	const press = () => onPress && onPress(text);
 
 	return (
 		<Touch
 			style={[styles.buttonView, { backgroundColor: 'transparent' }]}
-			underlayColor={themes[theme!].passcodeButtonActive}
-			rippleColor={themes[theme!].passcodeButtonActive}
+			underlayColor={themes[theme].passcodeButtonActive}
+			rippleColor={themes[theme].passcodeButtonActive}
 			enabled={!disabled}
 			theme={theme}
 			onPress={press}>
 			{icon ? (
-				<CustomIcon name={icon} size={36} color={themes[theme!].passcodePrimary} />
+				<CustomIcon name={icon} size={36} color={themes[theme].passcodePrimary} />
 			) : (
-				<Text style={[styles.buttonText, { color: themes[theme!].passcodePrimary }]}>{text}</Text>
+				<Text style={[styles.buttonText, { color: themes[theme].passcodePrimary }]}>{text}</Text>
 			)}
 		</Touch>
 	);
diff --git a/app/containers/message/interfaces.ts b/app/containers/message/interfaces.ts
index c9be40af9..866e7e40e 100644
--- a/app/containers/message/interfaces.ts
+++ b/app/containers/message/interfaces.ts
@@ -84,7 +84,7 @@ export interface IMessageContent {
 export interface IMessageDiscussion {
 	msg: string;
 	dcount: number;
-	dlm: string;
+	dlm: Date;
 	theme: string;
 }
 
diff --git a/app/definitions/ICommand.ts b/app/definitions/ICommand.ts
new file mode 100644
index 000000000..a0abeec26
--- /dev/null
+++ b/app/definitions/ICommand.ts
@@ -0,0 +1,6 @@
+export interface ICommand {
+	event: {
+		input: string;
+		modifierFlags: number;
+	};
+}
diff --git a/app/definitions/IServer.ts b/app/definitions/IServer.ts
index 014a2702b..0c3bf57d3 100644
--- a/app/definitions/IServer.ts
+++ b/app/definitions/IServer.ts
@@ -10,8 +10,8 @@ export interface IServer {
 	version: string;
 	lastLocalAuthenticatedSession: Date;
 	autoLock: boolean;
-	autoLockTime: number | null;
-	biometry: boolean | null;
+	autoLockTime?: number;
+	biometry?: boolean;
 	uniqueID: string;
 	enterpriseModules: string;
 	E2E_Enable: boolean;
diff --git a/app/definitions/ISubscription.ts b/app/definitions/ISubscription.ts
index 5f561edfb..1f241599a 100644
--- a/app/definitions/ISubscription.ts
+++ b/app/definitions/ISubscription.ts
@@ -79,6 +79,8 @@ export interface ISubscription {
 	avatarETag?: string;
 	teamId?: string;
 	teamMain?: boolean;
+	search?: boolean;
+	username?: string;
 	// https://nozbe.github.io/WatermelonDB/Relation.html#relation-api
 	messages: Relation<TMessageModel>;
 	threads: Relation<TThreadModel>;
diff --git a/app/definitions/ITheme.ts b/app/definitions/ITheme.ts
new file mode 100644
index 000000000..208a0b2d2
--- /dev/null
+++ b/app/definitions/ITheme.ts
@@ -0,0 +1,8 @@
+export type TThemeMode = 'automatic' | 'light' | 'dark';
+
+export type TDarkLevel = 'black' | 'dark';
+
+export interface IThemePreference {
+	currentTheme: TThemeMode;
+	darkLevel: TDarkLevel;
+}
diff --git a/app/externalModules.d.ts b/app/externalModules.d.ts
index f68cb5e39..02c57204f 100644
--- a/app/externalModules.d.ts
+++ b/app/externalModules.d.ts
@@ -13,3 +13,4 @@ declare module 'react-native-mime-types';
 declare module 'react-native-restart';
 declare module 'react-native-prompt-android';
 declare module 'react-native-jitsi-meet';
+declare module 'rn-root-view';
diff --git a/app/index.tsx b/app/index.tsx
index e6457e233..cc0a06a26 100644
--- a/app/index.tsx
+++ b/app/index.tsx
@@ -30,6 +30,8 @@ import InAppNotification from './containers/InAppNotification';
 import { ActionSheetProvider } from './containers/ActionSheet';
 import debounce from './utils/debounce';
 import { isFDroidBuild } from './constants/environment';
+import { IThemePreference } from './definitions/ITheme';
+import { ICommand } from './definitions/ICommand';
 
 RNScreens.enableScreens();
 
@@ -42,10 +44,7 @@ interface IDimensions {
 
 interface IState {
 	theme: string;
-	themePreferences: {
-		currentTheme: 'automatic' | 'light';
-		darkLevel: string;
-	};
+	themePreferences: IThemePreference;
 	width: number;
 	height: number;
 	scale: number;
@@ -175,7 +174,7 @@ export default class Root extends React.Component<{}, IState> {
 	setTheme = (newTheme = {}) => {
 		// change theme state
 		this.setState(
-			prevState => newThemeState(prevState, newTheme),
+			prevState => newThemeState(prevState, newTheme as IThemePreference),
 			() => {
 				const { themePreferences } = this.state;
 				// subscribe to Appearance changes
@@ -191,7 +190,7 @@ export default class Root extends React.Component<{}, IState> {
 	initTablet = () => {
 		const { width } = this.state;
 		this.setMasterDetail(width);
-		this.onKeyCommands = KeyCommandsEmitter.addListener('onKeyCommand', (command: unknown) => {
+		this.onKeyCommands = KeyCommandsEmitter.addListener('onKeyCommand', (command: ICommand) => {
 			EventEmitter.emit(KEY_COMMAND, { event: command });
 		});
 	};
diff --git a/app/share.tsx b/app/share.tsx
index daee2fba0..fbfcd0b52 100644
--- a/app/share.tsx
+++ b/app/share.tsx
@@ -14,6 +14,7 @@ import { defaultHeader, getActiveRouteName, navigationTheme, themedHeader } from
 import RocketChat, { THEME_PREFERENCES_KEY } from './lib/rocketchat';
 import { ThemeContext } from './theme';
 import { localAuthenticate } from './utils/localAuthentication';
+import { IThemePreference } from './definitions/ITheme';
 import ScreenLockedView from './views/ScreenLockedView';
 // Outside Stack
 import WithoutServersView from './views/WithoutServersView';
@@ -36,10 +37,7 @@ interface IDimensions {
 
 interface IState {
 	theme: string;
-	themePreferences: {
-		currentTheme: 'automatic' | 'light';
-		darkLevel: string;
-	};
+	themePreferences: IThemePreference;
 	root: any;
 	width: number;
 	height: number;
@@ -135,7 +133,7 @@ class Root extends React.Component<{}, IState> {
 	setTheme = (newTheme = {}) => {
 		// change theme state
 		this.setState(
-			prevState => newThemeState(prevState, newTheme),
+			prevState => newThemeState(prevState, newTheme as IThemePreference),
 			() => {
 				const { themePreferences } = this.state;
 				// subscribe to Appearance changes
diff --git a/app/theme.tsx b/app/theme.tsx
index 635ffda1c..9959cd768 100644
--- a/app/theme.tsx
+++ b/app/theme.tsx
@@ -1,12 +1,11 @@
 import React from 'react';
 import hoistNonReactStatics from 'hoist-non-react-statics';
 
+import { IThemePreference } from './definitions/ITheme';
+
 interface IThemeContextProps {
 	theme: string;
-	themePreferences?: {
-		currentTheme: 'automatic' | 'light';
-		darkLevel: string;
-	};
+	themePreferences?: IThemePreference;
 	setTheme?: (newTheme?: {}) => void;
 }
 
diff --git a/app/utils/appGroup.js b/app/utils/appGroup.ts
similarity index 83%
rename from app/utils/appGroup.js
rename to app/utils/appGroup.ts
index 63fb428aa..f92227c03 100644
--- a/app/utils/appGroup.js
+++ b/app/utils/appGroup.ts
@@ -4,7 +4,7 @@ import { isIOS } from './deviceInfo';
 
 const { AppGroup } = NativeModules;
 
-const appGroup = {
+const appGroup: { path: string } = {
 	path: isIOS ? AppGroup.path : ''
 };
 
diff --git a/app/utils/avatar.js b/app/utils/avatar.ts
similarity index 72%
rename from app/utils/avatar.js
rename to app/utils/avatar.ts
index 4cc15cdad..7e4b28195 100644
--- a/app/utils/avatar.js
+++ b/app/utils/avatar.ts
@@ -1,6 +1,8 @@
 import { compareServerVersion, methods } from '../lib/utils';
+import { SubscriptionType } from '../definitions/ISubscription';
+import { IAvatar } from '../containers/Avatar/interfaces';
 
-const formatUrl = (url, size, query) => `${url}?format=png&size=${size}${query}`;
+const formatUrl = (url: string, size: number, query: string) => `${url}?format=png&size=${size}${query}`;
 
 export const avatarURL = ({
 	type,
@@ -13,9 +15,9 @@ export const avatarURL = ({
 	rid,
 	blockUnauthenticatedAccess,
 	serverVersion
-}) => {
+}: IAvatar): string => {
 	let room;
-	if (type === 'd') {
+	if (type === SubscriptionType.DIRECT) {
 		room = text;
 	} else if (rid && !compareServerVersion(serverVersion, '3.6.0', methods.lowerThan)) {
 		room = `room/${rid}`;
diff --git a/app/utils/base64-js/index.js b/app/utils/base64-js/index.ts
similarity index 87%
rename from app/utils/base64-js/index.js
rename to app/utils/base64-js/index.ts
index 5616f71df..71fac91ce 100644
--- a/app/utils/base64-js/index.js
+++ b/app/utils/base64-js/index.ts
@@ -1,8 +1,8 @@
 /* eslint-disable no-bitwise */
 // https://github.com/beatgammit/base64-js/blob/master/index.js
 
-const lookup = [];
-const revLookup = [];
+const lookup: string[] = [];
+const revLookup: number[] = [];
 const Arr = typeof Uint8Array !== 'undefined' ? Uint8Array : Array;
 
 const code = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
@@ -16,7 +16,7 @@ for (let i = 0, len = code.length; i < len; i += 1) {
 revLookup['-'.charCodeAt(0)] = 62;
 revLookup['_'.charCodeAt(0)] = 63;
 
-const getLens = b64 => {
+const getLens = (b64: string) => {
 	const len = b64.length;
 
 	// We're encoding some strings not multiple of 4, so, disable this check
@@ -37,16 +37,17 @@ const getLens = b64 => {
 };
 
 // base64 is 4/3 + up to two characters of the original data
-export const byteLength = b64 => {
+export const byteLength = (b64: string) => {
 	const lens = getLens(b64);
 	const validLen = lens[0];
 	const placeHoldersLen = lens[1];
 	return ((validLen + placeHoldersLen) * 3) / 4 - placeHoldersLen;
 };
 
-const _byteLength = (b64, validLen, placeHoldersLen) => ((validLen + placeHoldersLen) * 3) / 4 - placeHoldersLen;
+const _byteLength = (b64: string, validLen: number, placeHoldersLen: number) =>
+	((validLen + placeHoldersLen) * 3) / 4 - placeHoldersLen;
 
-export const toByteArray = b64 => {
+export const toByteArray = (b64: string) => {
 	let tmp;
 	const lens = getLens(b64);
 	const validLen = lens[0];
@@ -92,10 +93,10 @@ export const toByteArray = b64 => {
 	return arr;
 };
 
-const tripletToBase64 = num =>
+const tripletToBase64 = (num: number) =>
 	lookup[(num >> 18) & 0x3f] + lookup[(num >> 12) & 0x3f] + lookup[(num >> 6) & 0x3f] + lookup[num & 0x3f];
 
-const encodeChunk = (uint8, start, end) => {
+const encodeChunk = (uint8: number[] | Uint8Array, start: number, end: number) => {
 	let tmp;
 	const output = [];
 	for (let i = start; i < end; i += 3) {
@@ -105,7 +106,7 @@ const encodeChunk = (uint8, start, end) => {
 	return output.join('');
 };
 
-export const fromByteArray = uint8 => {
+export const fromByteArray = (uint8: number[] | Uint8Array) => {
 	let tmp;
 	const len = uint8.length;
 	const extraBytes = len % 3; // if we have 1 byte left, pad 2 bytes
diff --git a/app/utils/debounce.js b/app/utils/debounce.js
deleted file mode 100644
index 106c61d00..000000000
--- a/app/utils/debounce.js
+++ /dev/null
@@ -1,20 +0,0 @@
-export default function debounce(func, wait, immediate) {
-	let timeout;
-	function _debounce(...args) {
-		const context = this;
-		const later = function __debounce() {
-			timeout = null;
-			if (!immediate) {
-				func.apply(context, args);
-			}
-		};
-		const callNow = immediate && !timeout;
-		clearTimeout(timeout);
-		timeout = setTimeout(later, wait);
-		if (callNow) {
-			func.apply(context, args);
-		}
-	}
-	_debounce.stop = () => clearTimeout(timeout);
-	return _debounce;
-}
diff --git a/app/utils/debounce.ts b/app/utils/debounce.ts
new file mode 100644
index 000000000..e0c28b239
--- /dev/null
+++ b/app/utils/debounce.ts
@@ -0,0 +1,22 @@
+export default function debounce(func: Function, wait?: number, immediate?: boolean) {
+	let timeout: number | null;
+	function _debounce(...args: any[]) {
+		// @ts-ignore
+		// eslint-disable-next-line @typescript-eslint/no-this-alias
+		const context = this;
+		const later = function __debounce() {
+			timeout = null;
+			if (!immediate) {
+				func.apply(context, args);
+			}
+		};
+		const callNow = immediate && !timeout;
+		clearTimeout(timeout!);
+		timeout = setTimeout(later, wait);
+		if (callNow) {
+			func.apply(context, args);
+		}
+	}
+	_debounce.stop = () => clearTimeout(timeout!);
+	return _debounce;
+}
diff --git a/app/utils/deviceInfo.js b/app/utils/deviceInfo.ts
similarity index 92%
rename from app/utils/deviceInfo.js
rename to app/utils/deviceInfo.ts
index 7961b440a..9cb7ac727 100644
--- a/app/utils/deviceInfo.js
+++ b/app/utils/deviceInfo.ts
@@ -9,7 +9,7 @@ export const getBundleId = DeviceInfo.getBundleId();
 export const getDeviceModel = DeviceInfo.getModel();
 
 // Theme is supported by system on iOS 13+ or Android 10+
-export const supportSystemTheme = () => {
+export const supportSystemTheme = (): boolean => {
 	const systemVersion = parseInt(DeviceInfo.getSystemVersion(), 10);
 	return systemVersion >= (isIOS ? 13 : 10);
 };
diff --git a/app/utils/events.js b/app/utils/events.ts
similarity index 53%
rename from app/utils/events.js
rename to app/utils/events.ts
index 8e67fc82e..fc0b975ad 100644
--- a/app/utils/events.js
+++ b/app/utils/events.ts
@@ -1,11 +1,25 @@
+import { ICommand } from '../definitions/ICommand';
 import log from './log';
 
+type TEventEmitterEmmitArgs =
+	| { rid: string }
+	| { message: string }
+	| { method: string }
+	| { invalid: boolean }
+	| { force: boolean }
+	| { hasBiometry: boolean }
+	| { event: string | ICommand }
+	| { cancel: () => void }
+	| { submit: (param: string) => void };
+
 class EventEmitter {
+	private events: { [key: string]: any };
+
 	constructor() {
 		this.events = {};
 	}
 
-	addEventListener(event, listener) {
+	addEventListener(event: string, listener: Function) {
 		if (typeof this.events[event] !== 'object') {
 			this.events[event] = [];
 		}
@@ -13,7 +27,7 @@ class EventEmitter {
 		return listener;
 	}
 
-	removeListener(event, listener) {
+	removeListener(event: string, listener: Function) {
 		if (typeof this.events[event] === 'object') {
 			const idx = this.events[event].indexOf(listener);
 			if (idx > -1) {
@@ -25,9 +39,9 @@ class EventEmitter {
 		}
 	}
 
-	emit(event, ...args) {
+	emit(event: string, ...args: TEventEmitterEmmitArgs[]) {
 		if (typeof this.events[event] === 'object') {
-			this.events[event].forEach(listener => {
+			this.events[event].forEach((listener: Function) => {
 				try {
 					listener.apply(this, args);
 				} catch (e) {
diff --git a/app/utils/fetch.js b/app/utils/fetch.ts
similarity index 75%
rename from app/utils/fetch.js
rename to app/utils/fetch.ts
index 84f5669ae..c8758da8b 100644
--- a/app/utils/fetch.js
+++ b/app/utils/fetch.ts
@@ -4,15 +4,20 @@ import { settings as RocketChatSettings } from '@rocket.chat/sdk';
 
 import RocketChat from '../lib/rocketchat';
 
+interface CustomHeaders {
+	'User-Agent': string;
+	Authorization?: string;
+}
+
 // this form is required by Rocket.Chat's parser in "app/statistics/server/lib/UAParserCustom.js"
-export const headers = {
+export const headers: CustomHeaders = {
 	'User-Agent': `RC Mobile; ${
 		Platform.OS
 	} ${DeviceInfo.getSystemVersion()}; v${DeviceInfo.getVersion()} (${DeviceInfo.getBuildNumber()})`
 };
 
 let _basicAuth;
-export const setBasicAuth = basicAuth => {
+export const setBasicAuth = (basicAuth: string): void => {
 	_basicAuth = basicAuth;
 	if (basicAuth) {
 		RocketChatSettings.customHeaders = { ...headers, Authorization: `Basic ${_basicAuth}` };
@@ -24,12 +29,15 @@ export const BASIC_AUTH_KEY = 'BASIC_AUTH_KEY';
 
 RocketChatSettings.customHeaders = headers;
 
-export default (url, options = {}) => {
+export default (url: string, options: { headers?: Headers; signal?: AbortSignal } = {}): Promise<Response> => {
 	let customOptions = { ...options, headers: RocketChatSettings.customHeaders };
 	if (options && options.headers) {
 		customOptions = { ...customOptions, headers: { ...options.headers, ...customOptions.headers } };
 	}
+	// TODO: Refactor when migrate rocketchat.js
+	// @ts-ignore
 	if (RocketChat.controller) {
+		// @ts-ignore
 		const { signal } = RocketChat.controller;
 		customOptions = { ...customOptions, signal };
 	}
diff --git a/app/utils/fileUpload/index.ios.js b/app/utils/fileUpload/index.ios.ts
similarity index 65%
rename from app/utils/fileUpload/index.ios.js
rename to app/utils/fileUpload/index.ios.ts
index a97640553..ae5cfabc2 100644
--- a/app/utils/fileUpload/index.ios.js
+++ b/app/utils/fileUpload/index.ios.ts
@@ -1,19 +1,25 @@
+import { IFileUpload } from './interfaces';
+
 class Upload {
+	public xhr: XMLHttpRequest;
+
+	public formData: FormData;
+
 	constructor() {
 		this.xhr = new XMLHttpRequest();
 		this.formData = new FormData();
 	}
 
-	then = callback => {
+	then = (callback: (param: { respInfo: XMLHttpRequest }) => XMLHttpRequest) => {
 		this.xhr.onload = () => callback({ respInfo: this.xhr });
 		this.xhr.send(this.formData);
 	};
 
-	catch = callback => {
+	catch = (callback: ((this: XMLHttpRequest, ev: ProgressEvent<EventTarget>) => any) | null) => {
 		this.xhr.onerror = callback;
 	};
 
-	uploadProgress = callback => {
+	uploadProgress = (callback: (param: number, arg1: number) => any) => {
 		this.xhr.upload.onprogress = ({ total, loaded }) => callback(loaded, total);
 	};
 
@@ -24,7 +30,7 @@ class Upload {
 }
 
 class FileUpload {
-	fetch = (method, url, headers, data) => {
+	fetch = (method: string, url: string, headers: { [x: string]: string }, data: IFileUpload[]) => {
 		const upload = new Upload();
 		upload.xhr.open(method, url);
 
@@ -35,6 +41,7 @@ class FileUpload {
 		data.forEach(item => {
 			if (item.uri) {
 				upload.formData.append(item.name, {
+					// @ts-ignore
 					uri: item.uri,
 					type: item.type,
 					name: item.filename
diff --git a/app/utils/fileUpload/index.android.js b/app/utils/fileUpload/index.ts
similarity index 64%
rename from app/utils/fileUpload/index.android.js
rename to app/utils/fileUpload/index.ts
index 5c45c27bd..1d2bdb312 100644
--- a/app/utils/fileUpload/index.android.js
+++ b/app/utils/fileUpload/index.ts
@@ -1,7 +1,11 @@
 import RNFetchBlob from 'rn-fetch-blob';
 
+import { IFileUpload } from './interfaces';
+
+type TMethods = 'POST' | 'GET' | 'DELETE' | 'PUT' | 'post' | 'get' | 'delete' | 'put';
+
 class FileUpload {
-	fetch = (method, url, headers, data) => {
+	fetch = (method: TMethods, url: string, headers: { [key: string]: string }, data: IFileUpload[]) => {
 		const formData = data.map(item => {
 			if (item.uri) {
 				return {
diff --git a/app/utils/fileUpload/interfaces.ts b/app/utils/fileUpload/interfaces.ts
new file mode 100644
index 000000000..a3002f727
--- /dev/null
+++ b/app/utils/fileUpload/interfaces.ts
@@ -0,0 +1,7 @@
+export interface IFileUpload {
+	name: string;
+	uri?: string;
+	type: string;
+	filename: string;
+	data: any;
+}
diff --git a/app/utils/goRoom.js b/app/utils/goRoom.ts
similarity index 58%
rename from app/utils/goRoom.js
rename to app/utils/goRoom.ts
index 1025a17d4..dc8a31882 100644
--- a/app/utils/goRoom.js
+++ b/app/utils/goRoom.ts
@@ -1,7 +1,17 @@
+import { ChatsStackParamList } from '../stacks/types';
 import Navigation from '../lib/Navigation';
 import RocketChat from '../lib/rocketchat';
+import { ISubscription, SubscriptionType } from '../definitions/ISubscription';
 
-const navigate = ({ item, isMasterDetail, ...props }) => {
+const navigate = ({
+	item,
+	isMasterDetail,
+	...props
+}: {
+	item: IItem;
+	isMasterDetail: boolean;
+	navigationMethod?: () => ChatsStackParamList;
+}) => {
 	let navigationMethod = props.navigationMethod ?? Navigation.navigate;
 
 	if (isMasterDetail) {
@@ -20,7 +30,22 @@ const navigate = ({ item, isMasterDetail, ...props }) => {
 	});
 };
 
-export const goRoom = async ({ item = {}, isMasterDetail = false, ...props }) => {
+interface IItem extends Partial<ISubscription> {
+	rid: string;
+	name: string;
+	t: SubscriptionType;
+}
+
+export const goRoom = async ({
+	item,
+	isMasterDetail = false,
+	...props
+}: {
+	item: IItem;
+	isMasterDetail: boolean;
+	navigationMethod?: any;
+	jumpToMessageId?: string;
+}): Promise<void> => {
 	if (item.t === 'd' && item.search) {
 		// if user is using the search we need first to join/create room
 		try {
@@ -30,8 +55,8 @@ export const goRoom = async ({ item = {}, isMasterDetail = false, ...props }) =>
 				return navigate({
 					item: {
 						rid: result.room._id,
-						name: username,
-						t: 'd'
+						name: username!,
+						t: SubscriptionType.DIRECT
 					},
 					isMasterDetail,
 					...props
diff --git a/app/utils/info.js b/app/utils/info.js
deleted file mode 100644
index 5d72f200e..000000000
--- a/app/utils/info.js
+++ /dev/null
@@ -1,25 +0,0 @@
-import { Alert } from 'react-native';
-
-import I18n from '../i18n';
-
-export const showErrorAlert = (message, title, onPress = () => {}) =>
-	Alert.alert(title, message, [{ text: 'OK', onPress }], { cancelable: true });
-
-export const showConfirmationAlert = ({ title, message, confirmationText, dismissText = I18n.t('Cancel'), onPress, onCancel }) =>
-	Alert.alert(
-		title || I18n.t('Are_you_sure_question_mark'),
-		message,
-		[
-			{
-				text: dismissText,
-				onPress: onCancel,
-				style: 'cancel'
-			},
-			{
-				text: confirmationText,
-				style: 'destructive',
-				onPress
-			}
-		],
-		{ cancelable: false }
-	);
diff --git a/app/utils/info.ts b/app/utils/info.ts
new file mode 100644
index 000000000..da882ee41
--- /dev/null
+++ b/app/utils/info.ts
@@ -0,0 +1,41 @@
+import { Alert } from 'react-native';
+
+import I18n from '../i18n';
+
+export const showErrorAlert = (message: string, title?: string, onPress = () => {}): void =>
+	Alert.alert(title!, message, [{ text: 'OK', onPress }], { cancelable: true });
+
+interface IShowConfirmationAlert {
+	title?: string;
+	message: string;
+	confirmationText: string;
+	dismissText?: string;
+	onPress: () => void;
+	onCancel?: () => void;
+}
+
+export const showConfirmationAlert = ({
+	title,
+	message,
+	confirmationText,
+	dismissText = I18n.t('Cancel'),
+	onPress,
+	onCancel
+}: IShowConfirmationAlert): void =>
+	Alert.alert(
+		title || I18n.t('Are_you_sure_question_mark'),
+		message,
+		[
+			{
+				text: dismissText,
+				onPress: onCancel,
+				style: 'cancel'
+			},
+			{
+				text: confirmationText,
+				style: 'destructive',
+				onPress
+			}
+		],
+		{ cancelable: false }
+	);
diff --git a/app/utils/isReadOnly.js b/app/utils/isReadOnly.ts
similarity index 59%
rename from app/utils/isReadOnly.js
rename to app/utils/isReadOnly.ts
index 62ae4fffe..d94b73c49 100644
--- a/app/utils/isReadOnly.js
+++ b/app/utils/isReadOnly.ts
@@ -1,16 +1,21 @@
 import RocketChat from '../lib/rocketchat';
 import reduxStore from '../lib/createStore';
+import { ISubscription } from '../definitions/ISubscription';
 
-const canPostReadOnly = async ({ rid }) => {
+const canPostReadOnly = async ({ rid }: { rid: string }) => {
 	// TODO: this is not reactive. If this permission changes, the component won't be updated
 	const postReadOnlyPermission = reduxStore.getState().permissions['post-readonly'];
 	const permission = await RocketChat.hasPermission([postReadOnlyPermission], rid);
 	return permission[0];
 };
 
-const isMuted = (room, user) => room && room.muted && room.muted.find && !!room.muted.find(m => m === user.username);
+const isMuted = (room: ISubscription, user: { username: string }) =>
+	room && room.muted && room.muted.find && !!room.muted.find(m => m === user.username);
 
-export const isReadOnly = async (room, user) => {
+export const isReadOnly = async (
+	room: ISubscription,
+	user: { id?: string; username: string; token?: string }
+): Promise<boolean> => {
 	if (room.archived) {
 		return true;
 	}
diff --git a/app/utils/isValidEmail.js b/app/utils/isValidEmail.ts
similarity index 78%
rename from app/utils/isValidEmail.js
rename to app/utils/isValidEmail.ts
index a8bd490f9..e230fc328 100644
--- a/app/utils/isValidEmail.js
+++ b/app/utils/isValidEmail.ts
@@ -1,4 +1,4 @@
-export default function isValidEmail(email) {
+export default function isValidEmail(email: string): boolean {
 	/* eslint-disable no-useless-escape */
 	const reg =
 		/^(([^<>()\[\]\\.,;:\s@"]+(\.[^<>()\[\]\\.,;:\s@"]+)*)|(".+"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;
diff --git a/app/utils/layoutAnimation.js b/app/utils/layoutAnimation.ts
similarity index 100%
rename from app/utils/layoutAnimation.js
rename to app/utils/layoutAnimation.ts
diff --git a/app/utils/localAuthentication.js b/app/utils/localAuthentication.ts
similarity index 73%
rename from app/utils/localAuthentication.js
rename to app/utils/localAuthentication.ts
index 29f256850..f43599633 100644
--- a/app/utils/localAuthentication.js
+++ b/app/utils/localAuthentication.ts
@@ -16,16 +16,17 @@ import {
 } from '../constants/localAuthentication';
 import I18n from '../i18n';
 import { setLocalAuthenticated } from '../actions/login';
+import { TServerModel } from '../definitions/IServer';
 import EventEmitter from './events';
 import { isIOS } from './deviceInfo';
 
-export const saveLastLocalAuthenticationSession = async (server, serverRecord) => {
+export const saveLastLocalAuthenticationSession = async (server: string, serverRecord?: TServerModel): Promise<void> => {
 	const serversDB = database.servers;
 	const serversCollection = serversDB.get('servers');
-	await serversDB.action(async () => {
+	await serversDB.write(async () => {
 		try {
 			if (!serverRecord) {
-				serverRecord = await serversCollection.find(server);
+				serverRecord = (await serversCollection.find(server)) as TServerModel;
 			}
 			await serverRecord.update(record => {
 				record.lastLocalAuthenticatedSession = new Date();
@@ -36,31 +37,31 @@ export const saveLastLocalAuthenticationSession = async (server, serverRecord) =
 	});
 };
 
-export const resetAttempts = () => AsyncStorage.multiRemove([LOCKED_OUT_TIMER_KEY, ATTEMPTS_KEY]);
+export const resetAttempts = (): Promise<void> => AsyncStorage.multiRemove([LOCKED_OUT_TIMER_KEY, ATTEMPTS_KEY]);
 
-const openModal = hasBiometry =>
-	new Promise(resolve => {
+const openModal = (hasBiometry: boolean) =>
+	new Promise<void>(resolve => {
 		EventEmitter.emit(LOCAL_AUTHENTICATE_EMITTER, {
 			submit: () => resolve(),
 			hasBiometry
 		});
 	});
 
-const openChangePasscodeModal = ({ force }) =>
-	new Promise((resolve, reject) => {
+const openChangePasscodeModal = ({ force }: { force: boolean }) =>
+	new Promise<string>((resolve, reject) => {
 		EventEmitter.emit(CHANGE_PASSCODE_EMITTER, {
-			submit: passcode => resolve(passcode),
+			submit: (passcode: string) => resolve(passcode),
 			cancel: () => reject(),
 			force
 		});
 	});
 
-export const changePasscode = async ({ force = false }) => {
+export const changePasscode = async ({ force = false }: { force: boolean }): Promise<void> => {
 	const passcode = await openChangePasscodeModal({ force });
 	await UserPreferences.setStringAsync(PASSCODE_KEY, sha256(passcode));
 };
 
-export const biometryAuth = force =>
+export const biometryAuth = (force?: boolean): Promise<LocalAuthentication.LocalAuthenticationResult> =>
 	LocalAuthentication.authenticateAsync({
 		disableDeviceFallback: true,
 		cancelLabel: force ? I18n.t('Dont_activate') : I18n.t('Local_authentication_biometry_fallback'),
@@ -71,11 +72,11 @@ export const biometryAuth = force =>
  * It'll help us to get the permission to use FaceID
  * and enable/disable the biometry when user put their first passcode
  */
-const checkBiometry = async serverRecord => {
+const checkBiometry = async (serverRecord: TServerModel) => {
 	const serversDB = database.servers;
 
 	const result = await biometryAuth(true);
-	await serversDB.action(async () => {
+	await serversDB.write(async () => {
 		try {
 			await serverRecord.update(record => {
 				record.biometry = !!result?.success;
@@ -86,7 +87,13 @@ const checkBiometry = async serverRecord => {
 	});
 };
 
-export const checkHasPasscode = async ({ force = true, serverRecord }) => {
+export const checkHasPasscode = async ({
+	force = true,
+	serverRecord
+}: {
+	force?: boolean;
+	serverRecord: TServerModel;
+}): Promise<{ newPasscode?: boolean } | void> => {
 	const storedPasscode = await UserPreferences.getStringAsync(PASSCODE_KEY);
 	if (!storedPasscode) {
 		await changePasscode({ force });
@@ -96,13 +103,13 @@ export const checkHasPasscode = async ({ force = true, serverRecord }) => {
 	return Promise.resolve();
 };
 
-export const localAuthenticate = async server => {
+export const localAuthenticate = async (server: string): Promise<void> => {
 	const serversDB = database.servers;
 	const serversCollection = serversDB.get('servers');
 
-	let serverRecord;
+	let serverRecord: TServerModel;
 	try {
-		serverRecord = await serversCollection.find(server);
+		serverRecord = (await serversCollection.find(server)) as TServerModel;
 	} catch (error) {
 		return Promise.reject();
 	}
@@ -125,7 +132,7 @@ export const localAuthenticate = async server => {
 			const diffToLastSession = moment().diff(serverRecord?.lastLocalAuthenticatedSession, 'seconds');
 
 			// if last authenticated session is older than configured auto lock time, authentication is required
-			if (diffToLastSession >= serverRecord?.autoLockTime) {
+			if (diffToLastSession >= serverRecord.autoLockTime!) {
 				// set isLocalAuthenticated to false
 				store.dispatch(setLocalAuthenticated(false));
 
@@ -150,7 +157,7 @@ export const localAuthenticate = async server => {
 	}
 };
 
-export const supportedBiometryLabel = async () => {
+export const supportedBiometryLabel = async (): Promise<string | null> => {
 	try {
 		const enrolled = await LocalAuthentication.isEnrolledAsync();
 
diff --git a/app/utils/log/events.js b/app/utils/log/events.ts
similarity index 100%
rename from app/utils/log/events.js
rename to app/utils/log/events.ts
diff --git a/app/utils/log/index.js b/app/utils/log/index.ts
similarity index 66%
rename from app/utils/log/index.js
rename to app/utils/log/index.ts
index 41074832f..d52bd0e94 100644
--- a/app/utils/log/index.js
+++ b/app/utils/log/index.ts
@@ -4,13 +4,13 @@ import { isFDroidBuild } from '../../constants/environment';
 import events from './events';
 
 const analytics = firebaseAnalytics || '';
-let bugsnag = '';
-let crashlytics;
+let bugsnag: any = '';
+let crashlytics: any;
 let reportCrashErrors = true;
 let reportAnalyticsEvents = true;
 
-export const getReportCrashErrorsValue = () => reportCrashErrors;
-export const getReportAnalyticsEventsValue = () => reportAnalyticsEvents;
+export const getReportCrashErrorsValue = (): boolean => reportCrashErrors;
+export const getReportAnalyticsEventsValue = (): boolean => reportAnalyticsEvents;
 
 if (!isFDroidBuild) {
 	bugsnag = require('@bugsnag/react-native').default;
@@ -18,7 +18,7 @@ if (!isFDroidBuild) {
 		onBreadcrumb() {
 			return reportAnalyticsEvents;
 		},
-		onError(error) {
+		onError(error: { breadcrumbs: string[] }) {
 			if (!reportAnalyticsEvents) {
 				error.breadcrumbs = [];
 			}
@@ -34,13 +34,13 @@ export { events };
 
 let metadata = {};
 
-export const logServerVersion = serverVersion => {
+export const logServerVersion = (serverVersion: string): void => {
 	metadata = {
 		serverVersion
 	};
 };
 
-export const logEvent = (eventName, payload) => {
+export const logEvent = (eventName: string, payload?: { [key: string]: any }): void => {
 	try {
 		if (!isFDroidBuild) {
 			analytics().logEvent(eventName, payload);
@@ -51,26 +51,26 @@ export const logEvent = (eventName, payload) => {
 	}
 };
 
-export const setCurrentScreen = currentScreen => {
+export const setCurrentScreen = (currentScreen: string): void => {
 	if (!isFDroidBuild) {
 		analytics().setCurrentScreen(currentScreen);
 		bugsnag.leaveBreadcrumb(currentScreen, { type: 'navigation' });
 	}
 };
 
-export const toggleCrashErrorsReport = value => {
+export const toggleCrashErrorsReport = (value: boolean): boolean => {
 	crashlytics().setCrashlyticsCollectionEnabled(value);
 	return (reportCrashErrors = value);
 };
 
-export const toggleAnalyticsEventsReport = value => {
+export const toggleAnalyticsEventsReport = (value: boolean): boolean => {
 	analytics().setAnalyticsCollectionEnabled(value);
 	return (reportAnalyticsEvents = value);
 };
 
-export default e => {
+export default (e: any): void => {
 	if (e instanceof Error && bugsnag && e.message !== 'Aborted' && !__DEV__) {
-		bugsnag.notify(e, event => {
+		bugsnag.notify(e, (event: { addMetadata: (arg0: string, arg1: {}) => void }) => {
 			event.addMetadata('details', { ...metadata });
 		});
 		if (!isFDroidBuild) {
diff --git a/app/utils/media.js b/app/utils/media.ts
similarity index 65%
rename from app/utils/media.js
rename to app/utils/media.ts
index 07f6f58d7..78b1c29f3 100644
--- a/app/utils/media.js
+++ b/app/utils/media.ts
@@ -1,4 +1,11 @@
-export const canUploadFile = (file, allowList, maxFileSize, permissionToUploadFile) => {
+import { IAttachment } from '../views/ShareView/interfaces';
+
+export const canUploadFile = (
+	file: IAttachment,
+	allowList: string,
+	maxFileSize: number,
+	permissionToUploadFile: boolean
+): { success: boolean; error?: string } => {
 	if (!(file && file.path)) {
 		return { success: true };
 	}
@@ -13,11 +20,11 @@ export const canUploadFile = (file, allowList, maxFileSize, permissionToUploadFi
 		return { success: true };
 	}
 	const allowedMime = allowList.split(',');
-	if (allowedMime.includes(file.mime)) {
+	if (allowedMime.includes(file.mime!)) {
 		return { success: true };
 	}
 	const wildCardGlob = '/*';
-	const wildCards = allowedMime.filter(item => item.indexOf(wildCardGlob) > 0);
+	const wildCards = allowedMime.filter((item: string) => item.indexOf(wildCardGlob) > 0);
 	if (file.mime && wildCards.includes(file.mime.replace(/(\/.*)$/, wildCardGlob))) {
 		return { success: true };
 	}
diff --git a/app/utils/messageTypes.js b/app/utils/messageTypes.ts
similarity index 100%
rename from app/utils/messageTypes.js
rename to app/utils/messageTypes.ts
diff --git a/app/utils/moment.js b/app/utils/moment.ts
similarity index 57%
rename from app/utils/moment.js
rename to app/utils/moment.ts
index 064b0f7f9..3379429c7 100644
--- a/app/utils/moment.js
+++ b/app/utils/moment.ts
@@ -1,4 +1,4 @@
-const localeKeys = {
+const localeKeys: { [key: string]: string } = {
 	en: 'en',
 	ru: 'ru',
 	'pt-BR': 'pt-br',
@@ -13,4 +13,4 @@ const localeKeys = {
 	'zh-TW': 'zh-tw'
 };
 
-export const toMomentLocale = locale => localeKeys[locale];
+export const toMomentLocale = (locale: string): string => localeKeys[locale];
diff --git a/app/utils/navigation/animations.js b/app/utils/navigation/animations.ts
similarity index 71%
rename from app/utils/navigation/animations.js
rename to app/utils/navigation/animations.ts
index 9f99764c4..a9f184088 100644
--- a/app/utils/navigation/animations.js
+++ b/app/utils/navigation/animations.ts
@@ -1,12 +1,14 @@
 import { Animated, Easing } from 'react-native';
-import { HeaderStyleInterpolators, TransitionPresets } from '@react-navigation/stack';
+import { HeaderStyleInterpolators, TransitionPreset, TransitionPresets } from '@react-navigation/stack';
+// eslint-disable-next-line import/no-unresolved
+import { StackCardStyleInterpolator, TransitionSpec } from '@react-navigation/stack/lib/typescript/src/types';
 
 import { isAndroid } from '../deviceInfo';
 import conditional from './conditional';
 
 const { multiply } = Animated;
 
-const forFadeFromCenter = ({ current, closing }) => {
+const forFadeFromCenter: StackCardStyleInterpolator = ({ current, closing }) => {
 	const opacity = conditional(
 		closing,
 		current.progress,
@@ -23,7 +25,7 @@ const forFadeFromCenter = ({ current, closing }) => {
 	};
 };
 
-const FadeIn = {
+const FadeIn: TransitionSpec = {
 	animation: 'timing',
 	config: {
 		duration: 250,
@@ -31,7 +33,7 @@ const FadeIn = {
 	}
 };
 
-const FadeOut = {
+const FadeOut: TransitionSpec = {
 	animation: 'timing',
 	config: {
 		duration: 150,
@@ -48,7 +50,7 @@ export const FadeFromCenterModal = {
 	cardStyleInterpolator: forFadeFromCenter
 };
 
-const forStackAndroid = ({ current, inverted, layouts: { screen } }) => {
+const forStackAndroid: StackCardStyleInterpolator = ({ current, inverted, layouts: { screen } }) => {
 	const translateX = multiply(
 		current.progress.interpolate({
 			inputRange: [0, 1],
@@ -70,7 +72,7 @@ const forStackAndroid = ({ current, inverted, layouts: { screen } }) => {
 	};
 };
 
-const StackAndroid = {
+const StackAndroid: TransitionPreset = {
 	gestureDirection: 'horizontal',
 	transitionSpec: {
 		open: FadeIn,
diff --git a/app/utils/navigation/conditional.js b/app/utils/navigation/conditional.ts
similarity index 87%
rename from app/utils/navigation/conditional.js
rename to app/utils/navigation/conditional.ts
index 015c52ae1..84c76d83a 100644
--- a/app/utils/navigation/conditional.js
+++ b/app/utils/navigation/conditional.ts
@@ -10,7 +10,11 @@ const { add, multiply } = Animated;
  * @param main Animated Node to use if the condition is `true`
  * @param fallback Animated Node to use if the condition is `false`
  */
-export default function conditional(condition, main, fallback) {
+export default function conditional(
+	condition: Animated.AnimatedInterpolation,
+	main: Animated.Animated,
+	fallback: Animated.Animated
+): Animated.AnimatedAddition {
 	// To implement this behavior, we multiply the main node with the condition.
 	// So if condition is 0, result will be 0, and if condition is 1, result will be main node.
 	// Then we multiple reverse of the condition (0 if condition is 1) with the fallback.
diff --git a/app/utils/openLink.js b/app/utils/openLink.ts
similarity index 83%
rename from app/utils/openLink.js
rename to app/utils/openLink.ts
index 92df16a70..4048b3add 100644
--- a/app/utils/openLink.js
+++ b/app/utils/openLink.ts
@@ -14,7 +14,7 @@ const scheme = {
 	brave: 'brave:'
 };
 
-const appSchemeURL = (url, browser) => {
+const appSchemeURL = (url: string, browser: string): string => {
 	let schemeUrl = url;
 	const parsedUrl = parse(url, true);
 	const { protocol } = parsedUrl;
@@ -35,7 +35,7 @@ const appSchemeURL = (url, browser) => {
 	return schemeUrl;
 };
 
-const openLink = async (url, theme = 'light') => {
+const openLink = async (url: string, theme = 'light'): Promise<void> => {
 	try {
 		const browser = await UserPreferences.getStringAsync(DEFAULT_BROWSER_KEY);
 
@@ -43,11 +43,12 @@ const openLink = async (url, theme = 'light') => {
 			await WebBrowser.openBrowserAsync(url, {
 				toolbarColor: themes[theme].headerBackground,
 				controlsColor: themes[theme].headerTintColor,
-				collapseToolbar: true,
+				// https://github.com/expo/expo/pull/4923
+				enableBarCollapsing: true,
 				showTitle: true
 			});
 		} else {
-			const schemeUrl = appSchemeURL(url, browser.replace(':', ''));
+			const schemeUrl = appSchemeURL(url, browser!.replace(':', ''));
 			await Linking.openURL(schemeUrl);
 		}
 	} catch {
diff --git a/app/utils/random.js b/app/utils/random.ts
similarity index 80%
rename from app/utils/random.js
rename to app/utils/random.ts
index 8f6adb880..2d2cd178b 100644
--- a/app/utils/random.js
+++ b/app/utils/random.ts
@@ -1,4 +1,4 @@
-export default function random(length) {
+export default function random(length: number): string {
 	let text = '';
 	const possible = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
 	for (let i = 0; i < length; i += 1) {
diff --git a/app/utils/review.js b/app/utils/review.ts
similarity index 96%
rename from app/utils/review.js
rename to app/utils/review.ts
index 15f1cf968..bbbb498be 100644
--- a/app/utils/review.js
+++ b/app/utils/review.ts
@@ -15,7 +15,7 @@ const reviewDelay = 2000;
 const numberOfDays = 7;
 const numberOfPositiveEvent = 5;
 
-const daysBetween = (date1, date2) => {
+const daysBetween = (date1: Date, date2: Date): number => {
 	const one_day = 1000 * 60 * 60 * 24;
 	const date1_ms = date1.getTime();
 	const date2_ms = date2.getTime();
@@ -32,7 +32,7 @@ const onCancelPress = () => {
 	}
 };
 
-export const onReviewPress = async () => {
+export const onReviewPress = async (): Promise<void> => {
 	logEvent(events.SE_REVIEW_THIS_APP);
 	await onCancelPress();
 	try {
diff --git a/app/utils/room.js b/app/utils/room.js
deleted file mode 100644
index 67df65a98..000000000
--- a/app/utils/room.js
+++ /dev/null
@@ -1,53 +0,0 @@
-import moment from 'moment';
-
-import { themes } from '../constants/colors';
-import I18n from '../i18n';
-
-export const isBlocked = room => {
-	if (room) {
-		const { t, blocked, blocker } = room;
-		if (t === 'd' && (blocked || blocker)) {
-			return true;
-		}
-	}
-	return false;
-};
-
-export const capitalize = s => {
-	if (typeof s !== 'string') {
-		return '';
-	}
-	return s.charAt(0).toUpperCase() + s.slice(1);
-};
-
-export const formatDate = date =>
-	moment(date).calendar(null, {
-		lastDay: `[${I18n.t('Yesterday')}]`,
-		sameDay: 'LT',
-		lastWeek: 'dddd',
-		sameElse: 'L'
-	});
-
-export const formatDateThreads = date =>
-	moment(date).calendar(null, {
-		sameDay: 'LT',
-		lastDay: `[${I18n.t('Yesterday')}] LT`,
-		lastWeek: 'dddd LT',
-		sameElse: 'LL'
-	});
-
-export const getBadgeColor = ({ subscription, messageId, theme }) => {
-	if (subscription?.tunreadUser?.includes(messageId)) {
-		return themes[theme].mentionMeColor;
-	}
-	if (subscription?.tunreadGroup?.includes(messageId)) {
-		return themes[theme].mentionGroupColor;
-	}
-	if (subscription?.tunread?.includes(messageId)) {
-		return themes[theme].tunreadColor;
-	}
-};
-
-export const makeThreadName = messageRecord => messageRecord.msg || messageRecord?.attachments[0]?.title;
-
-export const isTeamRoom = ({ teamId, joined }) => teamId && joined;
diff --git a/app/utils/room.ts b/app/utils/room.ts
new file mode 100644
index 000000000..3e4e0ef44
--- /dev/null
+++ b/app/utils/room.ts
@@ -0,0 +1,65 @@
+import moment from 'moment';
+
+import { themes } from '../constants/colors';
+import I18n from '../i18n';
+import { IAttachment } from '../definitions/IAttachment';
+import { ISubscription, SubscriptionType } from '../definitions/ISubscription';
+
+export const isBlocked = (room: ISubscription): boolean => {
+	if (room) {
+		const { t, blocked, blocker } = room;
+		if (t === SubscriptionType.DIRECT && (blocked || blocker)) {
+			return true;
+		}
+	}
+	return false;
+};
+
+export const capitalize = (s: string): string => {
+	if (typeof s !== 'string') {
+		return '';
+	}
+	return s.charAt(0).toUpperCase() + s.slice(1);
+};
+
+export const formatDate = (date: Date): string =>
+	moment(date).calendar(null, {
+		lastDay: `[${I18n.t('Yesterday')}]`,
+		sameDay: 'LT',
+		lastWeek: 'dddd',
+		sameElse: 'L'
+	});
+
+export const formatDateThreads = (date: Date): string =>
+	moment(date).calendar(null, {
+		sameDay: 'LT',
+		lastDay: `[${I18n.t('Yesterday')}] LT`,
+		lastWeek: 'dddd LT',
+		sameElse: 'LL'
+	});
+
+export const getBadgeColor = ({
+	subscription,
+	messageId,
+	theme
+}: {
+	// TODO: Refactor when migrate model folder
+	subscription: any;
+	messageId: string;
+	theme: string;
+}): string | undefined => {
+	if (subscription?.tunreadUser?.includes(messageId)) {
+		return themes[theme].mentionMeColor;
+	}
+	if (subscription?.tunreadGroup?.includes(messageId)) {
+		return themes[theme].mentionGroupColor;
+	}
+	if (subscription?.tunread?.includes(messageId)) {
+		return themes[theme].tunreadColor;
+	}
+};
+
+export const makeThreadName = (messageRecord: { id?: string; msg?: string; attachments?: IAttachment[] }): string | undefined =>
+	messageRecord.msg || messageRecord.attachments![0].title;
+
+export const isTeamRoom = ({ teamId, joined }: { teamId: string; joined: boolean }): boolean => !!teamId && joined;
diff --git a/app/utils/server.js b/app/utils/server.ts
similarity index 84%
rename from app/utils/server.js
rename to app/utils/server.ts
index e7be96b30..52064757b 100644
--- a/app/utils/server.js
+++ b/app/utils/server.ts
@@ -3,7 +3,7 @@
 	url = 'https://open.rocket.chat/method'
 	hostname = 'open.rocket.chat'
 */
-export const extractHostname = url => {
+export const extractHostname = (url: string): string => {
 	let hostname;
 
 	if (url.indexOf('//') > -1) {
diff --git a/app/utils/shortnameToUnicode/ascii.js b/app/utils/shortnameToUnicode/ascii.ts
similarity index 98%
rename from app/utils/shortnameToUnicode/ascii.js
rename to app/utils/shortnameToUnicode/ascii.ts
index 4d9d04cd3..7eca5f7df 100644
--- a/app/utils/shortnameToUnicode/ascii.js
+++ b/app/utils/shortnameToUnicode/ascii.ts
@@ -3,7 +3,7 @@
 /* eslint-disable object-curly-spacing */
 /* eslint-disable comma-spacing */
 /* eslint-disable key-spacing */
-const ascii = {
+const ascii: { [key: string]: string } = {
 	'*\\0/*': '🙆',
 	'*\\O/*': '🙆',
 	'-___-': '😑',
diff --git a/app/utils/shortnameToUnicode/emojis.js b/app/utils/shortnameToUnicode/emojis.ts
similarity index 99%
rename from app/utils/shortnameToUnicode/emojis.js
rename to app/utils/shortnameToUnicode/emojis.ts
index 14cd61337..6a8a63c3a 100644
--- a/app/utils/shortnameToUnicode/emojis.js
+++ b/app/utils/shortnameToUnicode/emojis.ts
@@ -3,7 +3,7 @@
 /* eslint-disable object-curly-spacing */
 /* eslint-disable comma-spacing */
 /* eslint-disable key-spacing */
-const emojis = {
+const emojis: { [key: string]: string } = {
 	':england:': '🏴󠁧󠁢󠁥󠁮󠁧󠁿',
 	':scotland:': '🏴󠁧󠁢󠁳󠁣󠁴󠁿',
 	':wales:': '🏴󠁧󠁢󠁷󠁬󠁳󠁿',
diff --git a/app/utils/shortnameToUnicode/index.js b/app/utils/shortnameToUnicode/index.ts
similarity index 80%
rename from app/utils/shortnameToUnicode/index.js
rename to app/utils/shortnameToUnicode/index.ts
index 0a54aa3a3..b533da8ff 100644
--- a/app/utils/shortnameToUnicode/index.js
+++ b/app/utils/shortnameToUnicode/index.ts
@@ -2,11 +2,11 @@ import emojis from './emojis';
 import ascii, { asciiRegexp } from './ascii';
 
 const shortnamePattern = new RegExp(/:[-+_a-z0-9]+:/, 'gi');
-const replaceShortNameWithUnicode = shortname => emojis[shortname] || shortname;
+const replaceShortNameWithUnicode = (shortname: string) => emojis[shortname] || shortname;
 const regAscii = new RegExp(`((\\s|^)${asciiRegexp}(?=\\s|$|[!,.?]))`, 'gi');
 
-const unescapeHTML = string => {
-	const unescaped = {
+const unescapeHTML = (string: string) => {
+	const unescaped: { [key: string]: string } = {
 		'&amp;': '&',
 		'&#38;': '&',
 		'&#x26;': '&',
@@ -27,7 +27,7 @@ const unescapeHTML = string => {
 	return string.replace(/&(?:amp|#38|#x26|lt|#60|#x3C|gt|#62|#x3E|apos|#39|#x27|quot|#34|#x22);/gi, match => unescaped[match]);
 };
 
-const shortnameToUnicode = str => {
+const shortnameToUnicode = (str: string): string => {
 	str = str.replace(shortnamePattern, replaceShortNameWithUnicode);
 
 	str = str.replace(regAscii, (entire, m1, m2, m3) => {
diff --git a/app/utils/sslPinning.js b/app/utils/sslPinning.ts
similarity index 75%
rename from app/utils/sslPinning.js
rename to app/utils/sslPinning.ts
index c3e2128c9..42245c98a 100644
--- a/app/utils/sslPinning.js
+++ b/app/utils/sslPinning.ts
@@ -9,13 +9,18 @@ import { extractHostname } from './server';
 const { SSLPinning } = NativeModules;
 const { documentDirectory } = FileSystem;
 
-const extractFileScheme = path => path.replace('file://', ''); // file:// isn't allowed by obj-C
+const extractFileScheme = (path: string) => path.replace('file://', ''); // file:// isn't allowed by obj-C
 
-const getPath = name => `${documentDirectory}/${name}`;
+const getPath = (name: string) => `${documentDirectory}/${name}`;
 
-const persistCertificate = async (name, password) => {
+interface ICertificate {
+	path: string;
+	password: string;
+}
+
+const persistCertificate = async (name: string, password: string) => {
 	const certificatePath = getPath(name);
-	const certificate = {
+	const certificate: ICertificate = {
 		path: extractFileScheme(certificatePath),
 		password
 	};
@@ -29,6 +34,7 @@ const RCSSLPinning = Platform.select({
 			new Promise(async (resolve, reject) => {
 				try {
 					const res = await DocumentPicker.pick({
+						// @ts-ignore
 						type: ['com.rsa.pkcs-12']
 					});
 					const { uri, name } = res;
@@ -42,7 +48,7 @@ const RCSSLPinning = Platform.select({
 									try {
 										const certificatePath = getPath(name);
 										await FileSystem.copyAsync({ from: uri, to: certificatePath });
-										await persistCertificate(name, password);
+										await persistCertificate(name, password!);
 										resolve(name);
 									} catch (e) {
 										reject(e);
@@ -56,10 +62,10 @@ const RCSSLPinning = Platform.select({
 					reject(e);
 				}
 			}),
-		setCertificate: async (name, server) => {
+		setCertificate: async (name: string, server: string) => {
 			if (name) {
-				let certificate = await UserPreferences.getMapAsync(name);
-				if (!certificate.path.match(extractFileScheme(documentDirectory))) {
+				let certificate = (await UserPreferences.getMapAsync(name)) as ICertificate;
+				if (!certificate.path.match(extractFileScheme(documentDirectory!))) {
 					certificate = await persistCertificate(name, certificate.password);
 				}
 				await UserPreferences.setMapAsync(extractHostname(server), certificate);
diff --git a/app/utils/theme.js b/app/utils/theme.ts
similarity index 71%
rename from app/utils/theme.js
rename to app/utils/theme.ts
index c9038941d..0e9d8e058 100644
--- a/app/utils/theme.js
+++ b/app/utils/theme.ts
@@ -2,12 +2,13 @@ import { Appearance } from 'react-native-appearance';
 import changeNavigationBarColor from 'react-native-navigation-bar-color';
 import setRootViewColor from 'rn-root-view';
 
+import { IThemePreference, TThemeMode } from '../definitions/ITheme';
 import { themes } from '../constants/colors';
 import { isAndroid } from './deviceInfo';
 
-let themeListener;
+let themeListener: { remove: () => void } | null;
 
-export const defaultTheme = () => {
+export const defaultTheme = (): TThemeMode => {
 	const systemTheme = Appearance.getColorScheme();
 	if (systemTheme && systemTheme !== 'no-preference') {
 		return systemTheme;
@@ -15,7 +16,7 @@ export const defaultTheme = () => {
 	return 'light';
 };
 
-export const getTheme = themePreferences => {
+export const getTheme = (themePreferences: IThemePreference): string => {
 	const { darkLevel, currentTheme } = themePreferences;
 	let theme = currentTheme;
 	if (currentTheme === 'automatic') {
@@ -24,7 +25,7 @@ export const getTheme = themePreferences => {
 	return theme === 'dark' ? darkLevel : 'light';
 };
 
-export const newThemeState = (prevState, newTheme) => {
+export const newThemeState = (prevState: { themePreferences: IThemePreference }, newTheme: IThemePreference) => {
 	// new theme preferences
 	const themePreferences = {
 		...prevState.themePreferences,
@@ -35,12 +36,13 @@ export const newThemeState = (prevState, newTheme) => {
 	return { themePreferences, theme: getTheme(themePreferences) };
 };
 
-export const setNativeTheme = async themePreferences => {
+export const setNativeTheme = async (themePreferences: IThemePreference): Promise<void> => {
 	const theme = getTheme(themePreferences);
 	if (isAndroid) {
 		const iconsLight = theme === 'light';
 		try {
-			await changeNavigationBarColor(themes[theme].navbarBackground, iconsLight);
+			// The late param as default is true @ react-native-navigation-bar-color/src/index.js line 8
+			await changeNavigationBarColor(themes[theme].navbarBackground, iconsLight, true);
 		} catch (error) {
 			// Do nothing
 		}
@@ -55,7 +57,7 @@ export const unsubscribeTheme = () => {
 	}
 };
 
-export const subscribeTheme = (themePreferences, setTheme) => {
+export const subscribeTheme = (themePreferences: IThemePreference, setTheme: () => void): void => {
 	const { currentTheme } = themePreferences;
 	if (!themeListener && currentTheme === 'automatic') {
 		// not use listener params because we use getTheme
diff --git a/app/utils/throttle.js b/app/utils/throttle.js
deleted file mode 100644
index 88751335f..000000000
--- a/app/utils/throttle.js
+++ /dev/null
@@ -1,26 +0,0 @@
-export default function throttle(fn, threshhold = 250, scope) {
-	let last;
-	let deferTimer;
-
-	const _throttle = (...args) => {
-		const context = scope || this;
-
-		const now = +new Date();
-
-		if (last && now < last + threshhold) {
-			// hold on to it
-			clearTimeout(deferTimer);
-			deferTimer = setTimeout(() => {
-				last = now;
-				fn.apply(context, args);
-			}, threshhold);
-		} else {
-			last = now;
-			fn.apply(context, args);
-		}
-	};
-
-	_throttle.stop = () => clearTimeout(deferTimer);
-
-	return _throttle;
-}
diff --git a/app/utils/touch.js b/app/utils/touch.tsx
similarity index 55%
rename from app/utils/touch.js
rename to app/utils/touch.tsx
index 0bfece04a..3573c87c5 100644
--- a/app/utils/touch.js
+++ b/app/utils/touch.tsx
@@ -1,19 +1,27 @@
 import React from 'react';
-import PropTypes from 'prop-types';
-import { RectButton } from 'react-native-gesture-handler';
+import { RectButton, RectButtonProps } from 'react-native-gesture-handler';
 
 import { themes } from '../constants/colors';
 
-class Touch extends React.Component {
-	setNativeProps(props) {
+interface ITouchProps extends RectButtonProps {
+	children: React.ReactNode;
+	theme: string;
+	accessibilityLabel?: string;
+	testID?: string;
+}
+
+class Touch extends React.Component<ITouchProps> {
+	private ref: any;
+
+	setNativeProps(props: ITouchProps): void {
 		this.ref.setNativeProps(props);
 	}
 
-	getRef = ref => {
+	getRef = (ref: RectButton): void => {
 		this.ref = ref;
 	};
 
-	render() {
+	render(): JSX.Element {
 		const { children, onPress, theme, underlayColor, ...props } = this.props;
 
 		return (
@@ -30,11 +38,4 @@ class Touch extends React.Component {
 	}
 }
 
-Touch.propTypes = {
-	children: PropTypes.node,
-	onPress: PropTypes.func,
-	theme: PropTypes.string,
-	underlayColor: PropTypes.string
-};
-
 export default Touch;
diff --git a/app/utils/twoFactor.js b/app/utils/twoFactor.ts
similarity index 68%
rename from app/utils/twoFactor.js
rename to app/utils/twoFactor.ts
index 6f2fa9c9d..a52ff93fd 100644
--- a/app/utils/twoFactor.js
+++ b/app/utils/twoFactor.ts
@@ -3,13 +3,18 @@ import { settings } from '@rocket.chat/sdk';
 import { TWO_FACTOR } from '../containers/TwoFactor';
 import EventEmitter from './events';
 
-export const twoFactor = ({ method, invalid }) =>
+interface ITwoFactor {
+	method: string;
+	invalid: boolean;
+}
+
+export const twoFactor = ({ method, invalid }: ITwoFactor): Promise<{ twoFactorCode: string; twoFactorMethod: string }> =>
 	new Promise((resolve, reject) => {
 		EventEmitter.emit(TWO_FACTOR, {
 			method,
 			invalid,
 			cancel: () => reject(),
-			submit: code => {
+			submit: (code: string) => {
 				settings.customHeaders = {
 					...settings.customHeaders,
 					'x-2fa-code': code,
diff --git a/app/utils/url.js b/app/utils/url.ts
similarity index 77%
rename from app/utils/url.js
rename to app/utils/url.ts
index 623524d7a..501795973 100644
--- a/app/utils/url.js
+++ b/app/utils/url.ts
@@ -1,4 +1,4 @@
-export const isValidURL = url => {
+export const isValidURL = (url: string): boolean => {
 	const pattern = new RegExp(
 		'^(https?:\\/\\/)?' + // protocol
 			'((([a-z\\d]([a-z\\d-]*[a-z\\d])*)\\.)+[a-z]{2,}|' + // domain name
@@ -12,4 +12,4 @@ export const isValidURL = url => {
 };
 
 // Use useSsl: false only if server url starts with http://
-export const useSsl = url => !/http:\/\//.test(url);
+export const useSsl = (url: string): boolean => !/http:\/\//.test(url);
diff --git a/app/views/CreateDiscussionView/SelectChannel.tsx b/app/views/CreateDiscussionView/SelectChannel.tsx
index e7653973f..41f7ab0b1 100644
--- a/app/views/CreateDiscussionView/SelectChannel.tsx
+++ b/app/views/CreateDiscussionView/SelectChannel.tsx
@@ -32,8 +32,6 @@ const SelectChannel = ({
 	}, 300);
 
 	const getAvatar = (item: any) =>
-		// TODO: remove this ts-ignore when migrate the file: app/utils/avatar.js
-		// @ts-ignore
 		avatarURL({
 			text: RocketChat.getRoomAvatar(item),
 			type: item.t,
diff --git a/app/views/CreateDiscussionView/SelectUsers.tsx b/app/views/CreateDiscussionView/SelectUsers.tsx
index 65a4e0a4a..d63c5ae6a 100644
--- a/app/views/CreateDiscussionView/SelectUsers.tsx
+++ b/app/views/CreateDiscussionView/SelectUsers.tsx
@@ -12,6 +12,7 @@ import { MultiSelect } from '../../containers/UIKit/MultiSelect';
 import { themes } from '../../constants/colors';
 import styles from './styles';
 import { ICreateDiscussionViewSelectUsers } from './interfaces';
+import { SubscriptionType } from '../../definitions/ISubscription';
 
 interface IUser {
 	name: string;
@@ -62,11 +63,9 @@ const SelectUsers = ({
 	}, 300);
 
 	const getAvatar = (item: any) =>
-		// TODO: remove this ts-ignore when migrate the file: app/utils/avatar.js
-		// @ts-ignore
 		avatarURL({
 			text: RocketChat.getRoomAvatar(item),
-			type: 'd',
+			type: SubscriptionType.DIRECT,
 			user: { id: userId, token },
 			server,
 			avatarETag: item.avatarETag,
diff --git a/app/views/CreateDiscussionView/interfaces.ts b/app/views/CreateDiscussionView/interfaces.ts
index e9d076b16..6009881c1 100644
--- a/app/views/CreateDiscussionView/interfaces.ts
+++ b/app/views/CreateDiscussionView/interfaces.ts
@@ -2,6 +2,7 @@ import { RouteProp } from '@react-navigation/core';
 import { StackNavigationProp } from '@react-navigation/stack';
 
 import { NewMessageStackParamList } from '../../stacks/types';
+import { SubscriptionType } from '../../definitions/ISubscription';
 
 export interface ICreateChannelViewProps {
 	navigation: StackNavigationProp<NewMessageStackParamList, 'CreateDiscussionView'>;
@@ -15,7 +16,7 @@ export interface ICreateChannelViewProps {
 	loading: boolean;
 	result: {
 		rid: string;
-		t: string;
+		t: SubscriptionType;
 		prid: string;
 	};
 	failure: boolean;
diff --git a/app/views/E2EEncryptionSecurityView.tsx b/app/views/E2EEncryptionSecurityView.tsx
index d5b0b27a2..347590430 100644
--- a/app/views/E2EEncryptionSecurityView.tsx
+++ b/app/views/E2EEncryptionSecurityView.tsx
@@ -75,8 +75,6 @@ class E2EEncryptionSecurityView extends React.Component<IE2EEncryptionSecurityVi
 		if (!newPassword.trim()) {
 			return;
 		}
-		// TODO: Remove ts-ignore when migrate the showConfirmationAlert
-		// @ts-ignore
 		showConfirmationAlert({
 			title: I18n.t('Are_you_sure_question_mark'),
 			message: I18n.t('E2E_encryption_change_password_message'),
@@ -98,8 +96,6 @@ class E2EEncryptionSecurityView extends React.Component<IE2EEncryptionSecurityVi
 	};
 
 	resetOwnKey = () => {
-		// TODO: Remove ts-ignore when migrate the showConfirmationAlert
-		// @ts-ignore
 		showConfirmationAlert({
 			title: I18n.t('Are_you_sure_question_mark'),
 			message: I18n.t('E2E_encryption_reset_message'),
diff --git a/app/views/NewServerView/index.tsx b/app/views/NewServerView/index.tsx
index 53594d9c0..93e493bea 100644
--- a/app/views/NewServerView/index.tsx
+++ b/app/views/NewServerView/index.tsx
@@ -269,11 +269,10 @@ class NewServerView extends React.Component<INewServerView, IState> {
 	uriToPath = (uri: string) => uri.replace('file://', '');
 
 	handleRemove = () => {
-		// TODO: Remove ts-ignore when migrate the showConfirmationAlert
-		// @ts-ignore
 		showConfirmationAlert({
 			message: I18n.t('You_will_unset_a_certificate_for_this_server'),
 			confirmationText: I18n.t('Remove'),
+			// @ts-ignore
 			onPress: this.setState({ certificate: null }) // We not need delete file from DocumentPicker because it is a temp file
 		});
 	};
diff --git a/app/views/ProfileView/index.tsx b/app/views/ProfileView/index.tsx
index d0ca64eec..fc409002d 100644
--- a/app/views/ProfileView/index.tsx
+++ b/app/views/ProfileView/index.tsx
@@ -424,7 +424,6 @@ class ProfileView extends React.Component<IProfileViewProps, IProfileViewState>
 
 	logoutOtherLocations = () => {
 		logEvent(events.PL_OTHER_LOCATIONS);
-		// @ts-ignore
 		showConfirmationAlert({
 			message: I18n.t('You_will_be_logged_out_from_other_locations'),
 			confirmationText: I18n.t('Logout'),
diff --git a/app/views/ProfileView/interfaces.ts b/app/views/ProfileView/interfaces.ts
index bfec50c0d..0fe592f32 100644
--- a/app/views/ProfileView/interfaces.ts
+++ b/app/views/ProfileView/interfaces.ts
@@ -26,9 +26,9 @@ export interface IParams {
 }
 
 export interface IAvatarButton {
-	key: React.Key;
+	key: string;
 	child: React.ReactNode;
-	onPress: Function;
+	onPress: () => void;
 	disabled: boolean;
 }
 
diff --git a/app/views/ScreenLockConfigView.tsx b/app/views/ScreenLockConfigView.tsx
index 57638f417..d6307f5e9 100644
--- a/app/views/ScreenLockConfigView.tsx
+++ b/app/views/ScreenLockConfigView.tsx
@@ -2,7 +2,6 @@ import React from 'react';
 import { Switch } from 'react-native';
 import { connect } from 'react-redux';
 import { StackNavigationOptions } from '@react-navigation/stack';
-import Model from '@nozbe/watermelondb/Model';
 import { Subscription } from 'rxjs';
 
 import I18n from '../i18n';
@@ -15,15 +14,10 @@ import { changePasscode, checkHasPasscode, supportedBiometryLabel } from '../uti
 import { DEFAULT_AUTO_LOCK } from '../constants/localAuthentication';
 import SafeAreaView from '../containers/SafeAreaView';
 import { events, logEvent } from '../utils/log';
+import { TServerModel } from '../definitions/IServer';
 
 const DEFAULT_BIOMETRY = false;
 
-interface IServerRecords extends Model {
-	autoLock?: boolean;
-	autoLockTime?: number;
-	biometry?: boolean;
-}
-
 interface IItem {
 	title: string;
 	value: number;
@@ -38,14 +32,14 @@ interface IScreenLockConfigViewProps {
 }
 
 interface IScreenLockConfigViewState {
-	autoLock?: boolean;
+	autoLock: boolean;
 	autoLockTime?: number | null;
 	biometry?: boolean;
-	biometryLabel: null;
+	biometryLabel: string | null;
 }
 
 class ScreenLockConfigView extends React.Component<IScreenLockConfigViewProps, IScreenLockConfigViewState> {
-	private serverRecord?: IServerRecords;
+	private serverRecord?: TServerModel;
 
 	private observable?: Subscription;
 
@@ -98,7 +92,7 @@ class ScreenLockConfigView extends React.Component<IScreenLockConfigViewProps, I
 		const serversDB = database.servers;
 		const serversCollection = serversDB.get('servers');
 		try {
-			this.serverRecord = await serversCollection.find(server);
+			this.serverRecord = (await serversCollection.find(server)) as TServerModel;
 			this.setState({
 				autoLock: this.serverRecord?.autoLock,
 				autoLockTime: this.serverRecord?.autoLockTime === null ? DEFAULT_AUTO_LOCK : this.serverRecord?.autoLockTime,
@@ -151,7 +145,7 @@ class ScreenLockConfigView extends React.Component<IScreenLockConfigViewProps, I
 				const { autoLock } = this.state;
 				if (autoLock) {
 					try {
-						await checkHasPasscode({ force: false, serverRecord: this.serverRecord });
+						await checkHasPasscode({ force: false, serverRecord: this.serverRecord! });
 					} catch {
 						this.toggleAutoLock();
 					}
diff --git a/app/views/SettingsView/index.tsx b/app/views/SettingsView/index.tsx
index edad2822e..3ab35b840 100644
--- a/app/views/SettingsView/index.tsx
+++ b/app/views/SettingsView/index.tsx
@@ -88,7 +88,6 @@ class SettingsView extends React.Component<ISettingsViewProps, any> {
 
 	handleLogout = () => {
 		logEvent(events.SE_LOG_OUT);
-		// @ts-ignore
 		showConfirmationAlert({
 			message: I18n.t('You_will_be_logged_out_of_this_application'),
 			confirmationText: I18n.t('Logout'),
@@ -98,7 +97,6 @@ class SettingsView extends React.Component<ISettingsViewProps, any> {
 
 	handleClearCache = () => {
 		logEvent(events.SE_CLEAR_LOCAL_SERVER_CACHE);
-		/* @ts-ignore */
 		showConfirmationAlert({
 			message: I18n.t('This_will_clear_all_your_offline_data'),
 			confirmationText: I18n.t('Clear'),
diff --git a/app/views/ShareListView/index.tsx b/app/views/ShareListView/index.tsx
index 1c9f0e415..e4294c600 100644
--- a/app/views/ShareListView/index.tsx
+++ b/app/views/ShareListView/index.tsx
@@ -25,12 +25,12 @@ import { sanitizeLikeString } from '../../lib/database/utils';
 import styles from './styles';
 import ShareListHeader from './Header';
 
-interface IFile {
+interface IDataFromShare {
 	value: string;
 	type: string;
 }
 
-interface IAttachment {
+interface IFileToShare {
 	filename: string;
 	description: string;
 	size: number;
@@ -61,7 +61,7 @@ interface IState {
 	searchResults: IChat[];
 	chats: IChat[];
 	serversCount: number;
-	attachments: IAttachment[];
+	attachments: IFileToShare[];
 	text: string;
 	loading: boolean;
 	serverInfo: IServerInfo;
@@ -121,7 +121,7 @@ class ShareListView extends React.Component<IShareListViewProps, IState> {
 	async componentDidMount() {
 		const { server } = this.props;
 		try {
-			const data = (await ShareExtension.data()) as IFile[];
+			const data = (await ShareExtension.data()) as IDataFromShare[];
 			if (isAndroid) {
 				await this.askForPermission(data);
 			}
@@ -136,7 +136,7 @@ class ShareListView extends React.Component<IShareListViewProps, IState> {
 				size: file.size,
 				mime: mime.lookup(file.uri),
 				path: file.uri
-			})) as IAttachment[];
+			})) as IFileToShare[];
 			const text = data.filter(item => item.type === 'text').reduce((acc, item) => `${item.value}\n${acc}`, '');
 			this.setState({
 				text,
@@ -294,7 +294,7 @@ class ShareListView extends React.Component<IShareListViewProps, IState> {
 		}
 	};
 
-	askForPermission = async (data: IFile[]) => {
+	askForPermission = async (data: IDataFromShare[]) => {
 		const mediaIndex = data.findIndex(item => item.type === 'media');
 		if (mediaIndex !== -1) {
 			const result = await PermissionsAndroid.request(PermissionsAndroid.PERMISSIONS.READ_EXTERNAL_STORAGE, permission);
diff --git a/app/views/ShareView/index.tsx b/app/views/ShareView/index.tsx
index d77ba022b..e91b8a326 100644
--- a/app/views/ShareView/index.tsx
+++ b/app/views/ShareView/index.tsx
@@ -39,7 +39,7 @@ interface IShareViewState {
 	room: ISubscription;
 	thread: any; // change
 	maxFileSize: number;
-	mediaAllowList: number;
+	mediaAllowList: string;
 }
 
 interface IShareViewProps {
@@ -52,7 +52,7 @@ interface IShareViewProps {
 		token: string;
 	};
 	server: string;
-	FileUpload_MediaTypeWhiteList?: number;
+	FileUpload_MediaTypeWhiteList?: string;
 	FileUpload_MaxFileSize?: number;
 }
 
diff --git a/app/views/ThemeView.tsx b/app/views/ThemeView.tsx
index 8ab9010c4..636dec487 100644
--- a/app/views/ThemeView.tsx
+++ b/app/views/ThemeView.tsx
@@ -11,17 +11,18 @@ import { supportSystemTheme } from '../utils/deviceInfo';
 import SafeAreaView from '../containers/SafeAreaView';
 import UserPreferences from '../lib/userPreferences';
 import { events, logEvent } from '../utils/log';
+import { IThemePreference, TThemeMode, TDarkLevel } from '../definitions/ITheme';
 
 const THEME_GROUP = 'THEME_GROUP';
 const DARK_GROUP = 'DARK_GROUP';
 
-const SYSTEM_THEME = {
+const SYSTEM_THEME: ITheme = {
 	label: 'Automatic',
 	value: 'automatic',
 	group: THEME_GROUP
 };
 
-const THEMES = [
+const THEMES: ITheme[] = [
 	{
 		label: 'Light',
 		value: 'light',
@@ -53,15 +54,10 @@ const darkGroup = THEMES.filter(item => item.group === DARK_GROUP);
 
 interface ITheme {
 	label: string;
-	value: string;
+	value: TThemeMode | TDarkLevel;
 	group: string;
 }
 
-interface IThemePreference {
-	currentTheme?: string;
-	darkLevel?: string;
-}
-
 interface IThemeViewProps {
 	theme: string;
 	themePreferences: IThemePreference;
@@ -89,19 +85,19 @@ class ThemeView extends React.Component<IThemeViewProps> {
 		const { themePreferences } = this.props;
 		const { darkLevel, currentTheme } = themePreferences;
 		const { value, group } = item;
-		let changes: IThemePreference = {};
+		let changes: Partial<IThemePreference> = {};
 		if (group === THEME_GROUP && currentTheme !== value) {
 			logEvent(events.THEME_SET_THEME_GROUP, { theme_group: value });
-			changes = { currentTheme: value };
+			changes = { currentTheme: value as TThemeMode };
 		}
 		if (group === DARK_GROUP && darkLevel !== value) {
 			logEvent(events.THEME_SET_DARK_LEVEL, { dark_level: value });
-			changes = { darkLevel: value };
+			changes = { darkLevel: value as TDarkLevel };
 		}
 		this.setTheme(changes);
 	};
 
-	setTheme = async (theme: IThemePreference) => {
+	setTheme = async (theme: Partial<IThemePreference>) => {
 		const { setTheme, themePreferences } = this.props;
 		const newTheme = { ...themePreferences, ...theme };
 		setTheme(newTheme);