diff --git a/app/locale.js b/app/locale.js
index ddf80159e8e..028dec12bdf 100644
--- a/app/locale.js
+++ b/app/locale.js
@@ -1,6 +1,7 @@
 const path = require('path');
 const fs = require('fs');
 const _ = require('lodash');
+const { setup } = require('../js/modules/i18n');
 
 function normalizeLocaleName(locale) {
   if (/^en-/.test(locale)) {
@@ -58,7 +59,10 @@ function load({ appLocale, logger } = {}) {
     messages = english;
   }
 
+  const i18n = setup(appLocale, messages);
+
   return {
+    i18n,
     name: localeName,
     messages,
   };
diff --git a/main.js b/main.js
index 3d6e0a19d75..1d969c4848b 100644
--- a/main.js
+++ b/main.js
@@ -421,7 +421,7 @@ async function readyForUpdates() {
 
   // Second, start checking for app updates
   try {
-    await updater.start(getMainWindow, locale.messages, logger);
+    await updater.start(getMainWindow, locale, logger);
   } catch (error) {
     logger.error(
       'Error starting update checks:',
diff --git a/test/i18n_test.js b/test/i18n_test.js
index c351887e786..3f5442ba2b7 100644
--- a/test/i18n_test.js
+++ b/test/i18n_test.js
@@ -8,6 +8,13 @@ describe('i18n', () => {
     it('returns message for given string', () => {
       assert.equal(i18n('reportIssue'), 'Report an issue');
     });
+    it('returns message with single substitution', () => {
+      const actual = i18n('cannotUpdateDetail', 'https://signal.org/download');
+      assert.equal(
+        actual,
+        'Signal Desktop failed to update, but there is a new version available. Please go to https://signal.org/download and install the new version manually, then either contact support or file a bug about this problem.'
+      );
+    });
     it('returns message with multiple substitutions', () => {
       const actual = i18n('theyChangedTheTimer', ['Someone', '5 minutes']);
       assert.equal(
diff --git a/ts/updater/common.ts b/ts/updater/common.ts
index bb5881d5f80..d4c462d1692 100644
--- a/ts/updater/common.ts
+++ b/ts/updater/common.ts
@@ -27,10 +27,13 @@ import { Dialogs } from '../types/Dialogs';
 import * as packageJson from '../../package.json';
 import { getSignatureFileName } from './signature';
 
-export type MessagesType = {
-  [key: string]: {
-    message: string;
-    description?: string;
+export type LocaleType = {
+  i18n: (key: string, placeholders: Array<string>) => string;
+  messages: {
+    [key: string]: {
+      message: string;
+      description?: string;
+    };
   };
 };
 
@@ -146,19 +149,19 @@ export async function downloadUpdate(
 
 async function showFallbackUpdateDialog(
   mainWindow: BrowserWindow,
-  messages: MessagesType
+  locale: LocaleType
 ) {
   const RESTART_BUTTON = 0;
   const LATER_BUTTON = 1;
   const options = {
     type: 'info',
     buttons: [
-      messages.autoUpdateRestartButtonLabel.message,
-      messages.autoUpdateLaterButtonLabel.message,
+      locale.messages.autoUpdateRestartButtonLabel.message,
+      locale.messages.autoUpdateLaterButtonLabel.message,
     ],
-    title: messages.autoUpdateNewVersionTitle.message,
-    message: messages.autoUpdateNewVersionMessage.message,
-    detail: messages.autoUpdateNewVersionInstructions.message,
+    title: locale.messages.autoUpdateNewVersionTitle.message,
+    message: locale.messages.autoUpdateNewVersionMessage.message,
+    detail: locale.messages.autoUpdateNewVersionInstructions.message,
     defaultId: LATER_BUTTON,
     cancelId: LATER_BUTTON,
   };
@@ -170,7 +173,7 @@ async function showFallbackUpdateDialog(
 
 export function showUpdateDialog(
   mainWindow: BrowserWindow,
-  messages: MessagesType,
+  locale: LocaleType,
   performUpdateCallback: () => void
 ): void {
   let ack = false;
@@ -185,20 +188,20 @@ export function showUpdateDialog(
 
   setTimeout(async () => {
     if (!ack) {
-      await showFallbackUpdateDialog(mainWindow, messages);
+      await showFallbackUpdateDialog(mainWindow, locale);
     }
   }, ACK_RENDER_TIMEOUT);
 }
 
 async function showFallbackCannotUpdateDialog(
   mainWindow: BrowserWindow,
-  messages: MessagesType
+  locale: LocaleType
 ) {
   const options = {
     type: 'error',
-    buttons: [messages.ok.message],
-    title: messages.cannotUpdate.message,
-    message: messages.cannotUpdateDetail.message,
+    buttons: [locale.messages.ok.message],
+    title: locale.messages.cannotUpdate.message,
+    message: locale.i18n('cannotUpdateDetail', ['https://signal.org/download']),
   };
 
   await dialog.showMessageBox(mainWindow, options);
@@ -206,7 +209,7 @@ async function showFallbackCannotUpdateDialog(
 
 export function showCannotUpdateDialog(
   mainWindow: BrowserWindow,
-  messages: MessagesType
+  locale: LocaleType
 ): void {
   let ack = false;
 
@@ -218,7 +221,7 @@ export function showCannotUpdateDialog(
 
   setTimeout(async () => {
     if (!ack) {
-      await showFallbackCannotUpdateDialog(mainWindow, messages);
+      await showFallbackCannotUpdateDialog(mainWindow, locale);
     }
   }, ACK_RENDER_TIMEOUT);
 }
diff --git a/ts/updater/index.ts b/ts/updater/index.ts
index 0724319bb53..17276260e78 100644
--- a/ts/updater/index.ts
+++ b/ts/updater/index.ts
@@ -3,13 +3,13 @@ import { BrowserWindow } from 'electron';
 
 import { start as startMacOS } from './macos';
 import { start as startWindows } from './windows';
-import { LoggerType, MessagesType } from './common';
+import { LocaleType, LoggerType } from './common';
 
 let initialized = false;
 
 export async function start(
   getMainWindow: () => BrowserWindow,
-  messages?: MessagesType,
+  locale?: LocaleType,
   logger?: LoggerType
 ) {
   const { platform } = process;
@@ -19,8 +19,8 @@ export async function start(
   }
   initialized = true;
 
-  if (!messages) {
-    throw new Error('updater/start: Must provide messages!');
+  if (!locale) {
+    throw new Error('updater/start: Must provide locale!');
   }
   if (!logger) {
     throw new Error('updater/start: Must provide logger!');
@@ -35,9 +35,9 @@ export async function start(
   }
 
   if (platform === 'win32') {
-    await startWindows(getMainWindow, messages, logger);
+    await startWindows(getMainWindow, locale, logger);
   } else if (platform === 'darwin') {
-    await startMacOS(getMainWindow, messages, logger);
+    await startMacOS(getMainWindow, locale, logger);
   } else {
     throw new Error('updater/start: Unsupported platform');
   }
diff --git a/ts/updater/macos.ts b/ts/updater/macos.ts
index cfd697d3560..c5d7e15c35a 100644
--- a/ts/updater/macos.ts
+++ b/ts/updater/macos.ts
@@ -15,8 +15,8 @@ import {
   deleteTempDir,
   downloadUpdate,
   getPrintableError,
+  LocaleType,
   LoggerType,
-  MessagesType,
   showCannotUpdateDialog,
   showUpdateDialog,
 } from './common';
@@ -31,7 +31,7 @@ const INTERVAL = MINUTE * 30;
 
 export async function start(
   getMainWindow: () => BrowserWindow,
-  messages: MessagesType,
+  locale: LocaleType,
   logger: LoggerType
 ) {
   logger.info('macos/start: starting checks...');
@@ -41,13 +41,13 @@ export async function start(
 
   setInterval(async () => {
     try {
-      await checkDownloadAndInstall(getMainWindow, messages, logger);
+      await checkDownloadAndInstall(getMainWindow, locale, logger);
     } catch (error) {
       logger.error('macos/start: error:', getPrintableError(error));
     }
   }, INTERVAL);
 
-  await checkDownloadAndInstall(getMainWindow, messages, logger);
+  await checkDownloadAndInstall(getMainWindow, locale, logger);
 }
 
 let fileName: string;
@@ -57,7 +57,7 @@ let loggerForQuitHandler: LoggerType;
 
 async function checkDownloadAndInstall(
   getMainWindow: () => BrowserWindow,
-  messages: MessagesType,
+  locale: LocaleType,
   logger: LoggerType
 ) {
   if (isChecking) {
@@ -98,12 +98,12 @@ async function checkDownloadAndInstall(
       const message: string = error.message || '';
       if (message.includes(readOnly)) {
         logger.info('checkDownloadAndInstall: showing read-only dialog...');
-        showReadOnlyDialog(getMainWindow(), messages);
+        showReadOnlyDialog(getMainWindow(), locale);
       } else {
         logger.info(
           'checkDownloadAndInstall: showing general update failure dialog...'
         );
-        showCannotUpdateDialog(getMainWindow(), messages);
+        showCannotUpdateDialog(getMainWindow(), locale);
       }
 
       throw error;
@@ -114,7 +114,7 @@ async function checkDownloadAndInstall(
 
     logger.info('checkDownloadAndInstall: showing update dialog...');
 
-    showUpdateDialog(getMainWindow(), messages, () => {
+    showUpdateDialog(getMainWindow(), locale, () => {
       logger.info('checkDownloadAndInstall: calling quitAndInstall...');
       markShouldQuit();
       autoUpdater.quitAndInstall();
@@ -341,7 +341,7 @@ function shutdown(
 
 export function showReadOnlyDialog(
   mainWindow: BrowserWindow,
-  messages: MessagesType
+  locale: LocaleType
 ): void {
   let ack = false;
 
@@ -353,20 +353,20 @@ export function showReadOnlyDialog(
 
   setTimeout(async () => {
     if (!ack) {
-      await showFallbackReadOnlyDialog(mainWindow, messages);
+      await showFallbackReadOnlyDialog(mainWindow, locale);
     }
   }, ACK_RENDER_TIMEOUT);
 }
 
 async function showFallbackReadOnlyDialog(
   mainWindow: BrowserWindow,
-  messages: MessagesType
+  locale: LocaleType
 ) {
   const options = {
     type: 'warning',
-    buttons: [messages.ok.message],
-    title: messages.cannotUpdate.message,
-    message: messages.readOnlyVolume.message,
+    buttons: [locale.messages.ok.message],
+    title: locale.messages.cannotUpdate.message,
+    message: locale.i18n('readOnlyVolume', ['Signal.app', '/Applications']),
   };
 
   await dialog.showMessageBox(mainWindow, options);
diff --git a/ts/updater/windows.ts b/ts/updater/windows.ts
index e1295b85a83..586d1e933ba 100644
--- a/ts/updater/windows.ts
+++ b/ts/updater/windows.ts
@@ -12,8 +12,8 @@ import {
   deleteTempDir,
   downloadUpdate,
   getPrintableError,
+  LocaleType,
   LoggerType,
-  MessagesType,
   showCannotUpdateDialog,
   showUpdateDialog,
 } from './common';
@@ -30,7 +30,7 @@ const INTERVAL = MINUTE * 30;
 
 export async function start(
   getMainWindow: () => BrowserWindow,
-  messages: MessagesType,
+  locale: LocaleType,
   logger: LoggerType
 ) {
   logger.info('windows/start: starting checks...');
@@ -40,14 +40,14 @@ export async function start(
 
   setInterval(async () => {
     try {
-      await checkDownloadAndInstall(getMainWindow, messages, logger);
+      await checkDownloadAndInstall(getMainWindow, locale, logger);
     } catch (error) {
       logger.error('windows/start: error:', getPrintableError(error));
     }
   }, INTERVAL);
 
   await deletePreviousInstallers(logger);
-  await checkDownloadAndInstall(getMainWindow, messages, logger);
+  await checkDownloadAndInstall(getMainWindow, locale, logger);
 }
 
 let fileName: string;
@@ -58,7 +58,7 @@ let loggerForQuitHandler: LoggerType;
 
 async function checkDownloadAndInstall(
   getMainWindow: () => BrowserWindow,
-  messages: MessagesType,
+  locale: LocaleType,
   logger: LoggerType
 ) {
   if (isChecking) {
@@ -93,7 +93,7 @@ async function checkDownloadAndInstall(
     }
 
     logger.info('checkDownloadAndInstall: showing dialog...');
-    showUpdateDialog(getMainWindow(), messages, async () => {
+    showUpdateDialog(getMainWindow(), locale, async () => {
       try {
         await verifyAndInstall(updateFilePath, version, logger);
         installing = true;
@@ -101,7 +101,7 @@ async function checkDownloadAndInstall(
         logger.info(
           'checkDownloadAndInstall: showing general update failure dialog...'
         );
-        showCannotUpdateDialog(getMainWindow(), messages);
+        showCannotUpdateDialog(getMainWindow(), locale);
 
         throw error;
       }
diff --git a/ts/util/lint/exceptions.json b/ts/util/lint/exceptions.json
index 06282612f68..67b352ac325 100644
--- a/ts/util/lint/exceptions.json
+++ b/ts/util/lint/exceptions.json
@@ -3,7 +3,7 @@
     "rule": "jQuery-load(",
     "path": "app/locale.js",
     "line": "function load({ appLocale, logger } = {}) {",
-    "lineNumber": 27,
+    "lineNumber": 28,
     "reasonCategory": "falseMatch",
     "updated": "2018-09-13T21:20:44.234Z"
   },