diff --git a/.babelrc b/.babelrc
index af736e9c19..f75a9f82ef 100644
--- a/.babelrc
+++ b/.babelrc
@@ -15,6 +15,7 @@
     ],
     "plugins": [
         ["@babel/plugin-proposal-decorators", { "legacy": true }],
+        "@babel/plugin-proposal-export-default-from",
         "@babel/plugin-proposal-numeric-separator",
         "@babel/plugin-proposal-class-properties",
         "@babel/plugin-proposal-object-rest-spread",
diff --git a/package.json b/package.json
index 99e4983d60..a6f9e5076f 100644
--- a/package.json
+++ b/package.json
@@ -9,27 +9,27 @@
   },
   "license": "Apache-2.0",
   "files": [
+    "lib",
+    "res",
+    "src",
+    "scripts",
+    "git-revision.txt",
+    "docs",
+    "header",
     "CHANGELOG.md",
     "CONTRIBUTING.rst",
     "LICENSE",
     "README.md",
-    "code_style.md",
-    "git-revision.txt",
-    "header",
-    "lib",
-    "package.json",
-    "scripts",
-    "docs",
-    "src",
-    "res"
+    "package.json"
   ],
   "bin": {
     "reskindex": "scripts/reskindex.js",
     "matrix-gen-i18n": "scripts/gen-i18n.js",
     "matrix-prune-i18n": "scripts/prune-i18n.js"
   },
-  "main": "lib/index.js",
-  "typings": "lib/index.d.ts",
+  "main": "./lib/index.js",
+  "typings": "./lib/index.d.ts",
+  "matrix_src_main": "./src/index.js",
   "scripts": {
     "i18n": "matrix-gen-i18n",
     "prunei18n": "matrix-prune-i18n",
@@ -40,7 +40,7 @@
     "rethemendex": "res/css/rethemendex.sh",
     "clean": "rimraf lib",
     "build": "yarn clean && git rev-parse HEAD > git-revision.txt && yarn build:compile && yarn build:types",
-    "build:compile": "yarn reskindex && babel src -s -d lib --verbose --extensions \".ts,.js\"",
+    "build:compile": "yarn reskindex && babel -d lib --verbose --extensions \".ts,.js\" src",
     "build:types": "tsc --emitDeclarationOnly",
     "start": "echo THIS IS FOR LEGACY PURPOSES ONLY. && yarn start:all",
     "start:all": "concurrently --kill-others-on-fail --prefix \"{time} [{name}]\" -n build,reskindex \"yarn start:build\" \"yarn reskindex:watch\"",
@@ -114,6 +114,7 @@
     "@babel/core": "^7.7.5",
     "@babel/plugin-proposal-class-properties": "^7.7.4",
     "@babel/plugin-proposal-decorators": "^7.7.4",
+    "@babel/plugin-proposal-export-default-from": "^7.7.4",
     "@babel/plugin-proposal-numeric-separator": "^7.7.4",
     "@babel/plugin-proposal-object-rest-spread": "^7.7.4",
     "@babel/plugin-transform-flow-comments": "^7.7.4",
diff --git a/res/css/views/context_menus/_StatusMessageContextMenu.scss b/res/css/views/context_menus/_StatusMessageContextMenu.scss
index 972f608caf..2c8d608950 100644
--- a/res/css/views/context_menus/_StatusMessageContextMenu.scss
+++ b/res/css/views/context_menus/_StatusMessageContextMenu.scss
@@ -61,5 +61,5 @@ input.mx_StatusMessageContextMenu_message {
 }
 
 .mx_StatusMessageContextMenu_actionContainer .mx_Spinner {
-    justify-content: start;
+    justify-content: flex-start;
 }
diff --git a/res/css/views/dialogs/_CreateRoomDialog.scss b/res/css/views/dialogs/_CreateRoomDialog.scss
index d3a8f6ff42..7416ec2ef4 100644
--- a/res/css/views/dialogs/_CreateRoomDialog.scss
+++ b/res/css/views/dialogs/_CreateRoomDialog.scss
@@ -30,7 +30,7 @@ limitations under the License.
 
     > div {
         display: flex;
-        align-items: start;
+        align-items: flex-start;
         margin: 5px 0;
 
         input[type=checkbox] {
diff --git a/res/css/views/dialogs/keybackup/_CreateKeyBackupDialog.scss b/res/css/views/dialogs/keybackup/_CreateKeyBackupDialog.scss
index 7ba5f01a76..04ee575867 100644
--- a/res/css/views/dialogs/keybackup/_CreateKeyBackupDialog.scss
+++ b/res/css/views/dialogs/keybackup/_CreateKeyBackupDialog.scss
@@ -32,7 +32,7 @@ limitations under the License.
 
 .mx_CreateKeyBackupDialog_passPhraseContainer {
     display: flex;
-    align-items: start;
+    align-items: flex-start;
 }
 
 .mx_CreateKeyBackupDialog_passPhraseHelp {
diff --git a/res/css/views/dialogs/secretstorage/_CreateSecretStorageDialog.scss b/res/css/views/dialogs/secretstorage/_CreateSecretStorageDialog.scss
index 757d8028f0..5899abdf73 100644
--- a/res/css/views/dialogs/secretstorage/_CreateSecretStorageDialog.scss
+++ b/res/css/views/dialogs/secretstorage/_CreateSecretStorageDialog.scss
@@ -33,7 +33,7 @@ limitations under the License.
 
 .mx_CreateSecretStorageDialog_passPhraseContainer {
     display: flex;
-    align-items: start;
+    align-items: flex-start;
 }
 
 .mx_CreateSecretStorageDialog_passPhraseHelp {
diff --git a/res/css/views/rooms/_MemberDeviceInfo.scss b/res/css/views/rooms/_MemberDeviceInfo.scss
index e73e6c58f1..15b4832dc5 100644
--- a/res/css/views/rooms/_MemberDeviceInfo.scss
+++ b/res/css/views/rooms/_MemberDeviceInfo.scss
@@ -17,7 +17,7 @@ limitations under the License.
 .mx_MemberDeviceInfo {
     display: flex;
     padding-bottom: 10px;
-    align-items: start;
+    align-items: flex-start;
 }
 
 .mx_MemberDeviceInfo_icon {
diff --git a/res/css/views/rooms/_MessageComposer.scss b/res/css/views/rooms/_MessageComposer.scss
index 12e45a07c9..5efca51844 100644
--- a/res/css/views/rooms/_MessageComposer.scss
+++ b/res/css/views/rooms/_MessageComposer.scss
@@ -101,7 +101,7 @@ limitations under the License.
     display: flex;
     flex-direction: column;
     min-height: 60px;
-    justify-content: start;
+    justify-content: flex-start;
     align-items: flex-start;
     font-size: 14px;
     margin-right: 6px;
diff --git a/src/Avatar.js b/src/Avatar.js
index 1039ab1bb1..9ac5312c3a 100644
--- a/src/Avatar.js
+++ b/src/Avatar.js
@@ -32,7 +32,7 @@ export function avatarUrlForMember(member, width, height, resizeMethod) {
         // member can be null here currently since on invites, the JS SDK
         // does not have enough info to build a RoomMember object for
         // the inviter.
-        url = this.defaultAvatarUrlForString(member ? member.userId : '');
+        url = defaultAvatarUrlForString(member ? member.userId : '');
     }
     return url;
 }
diff --git a/src/Skinner.js b/src/Skinner.js
index fee234d77e..3baecc9fb3 100644
--- a/src/Skinner.js
+++ b/src/Skinner.js
@@ -58,7 +58,7 @@ class Skinner {
         // components have to be functions.
         const validType = typeof comp === 'function';
         if (!validType) {
-            throw new Error(`Not a valid component: ${name}.`);
+            throw new Error(`Not a valid component: ${name} (type = ${typeof(comp)}).`);
         }
         return comp;
     }
diff --git a/src/Unread.js b/src/Unread.js
index f82c0899b5..ca713b05e4 100644
--- a/src/Unread.js
+++ b/src/Unread.js
@@ -77,7 +77,7 @@ export function doesRoomHaveUnreadMessages(room) {
             // that counts and we can stop looking because the user's read
             // this and everything before.
             return false;
-        } else if (!shouldHideEvent(ev) && this.eventTriggersUnreadCount(ev)) {
+        } else if (!shouldHideEvent(ev) && eventTriggersUnreadCount(ev)) {
             // We've found a message that counts before we hit
             // the user's read receipt, so this room is definitely unread.
             return true;
diff --git a/src/languageHandler.js b/src/languageHandler.js
index 4aa22f3e65..c31db5eb5b 100644
--- a/src/languageHandler.js
+++ b/src/languageHandler.js
@@ -336,6 +336,10 @@ export function getLanguagesFromBrowser() {
     return [navigator.userLanguage || "en"];
 }
 
+export function getLanguageFromBrowser() {
+    return getLanguagesFromBrowser()[0];
+}
+
 /**
  * Turns a language string, normalises it,
  * (see normalizeLanguageKey) into an array of language strings
diff --git a/yarn.lock b/yarn.lock
index 4e1be061bc..3dba7da904 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -320,6 +320,14 @@
     "@babel/helper-plugin-utils" "^7.0.0"
     "@babel/plugin-syntax-dynamic-import" "^7.7.4"
 
+"@babel/plugin-proposal-export-default-from@^7.7.4":
+  version "7.7.4"
+  resolved "https://registry.yarnpkg.com/@babel/plugin-proposal-export-default-from/-/plugin-proposal-export-default-from-7.7.4.tgz#890de3c0c475374638292df31f6582160b54d639"
+  integrity sha512-1t6dh7BHYUz4zD1m4pozYYEZy/3m8dgOr9owx3r0mPPI3iGKRUKUbIxfYmcJ4hwljs/dhd0qOTr1ZDUp43ix+w==
+  dependencies:
+    "@babel/helper-plugin-utils" "^7.0.0"
+    "@babel/plugin-syntax-export-default-from" "^7.7.4"
+
 "@babel/plugin-proposal-json-strings@^7.7.4":
   version "7.7.4"
   resolved "https://registry.yarnpkg.com/@babel/plugin-proposal-json-strings/-/plugin-proposal-json-strings-7.7.4.tgz#7700a6bfda771d8dc81973249eac416c6b4c697d"
@@ -381,6 +389,13 @@
   dependencies:
     "@babel/helper-plugin-utils" "^7.0.0"
 
+"@babel/plugin-syntax-export-default-from@^7.7.4":
+  version "7.7.4"
+  resolved "https://registry.yarnpkg.com/@babel/plugin-syntax-export-default-from/-/plugin-syntax-export-default-from-7.7.4.tgz#897f05808298060b52873fa804ff853540790ea1"
+  integrity sha512-j888jpjATLEzOWhKawq46UrpXnCRDbdhBd5io4jgwjJ3+CHHGCRb6PNAVEgs+BXIb+dNRAmnkv36zfB992PRVw==
+  dependencies:
+    "@babel/helper-plugin-utils" "^7.0.0"
+
 "@babel/plugin-syntax-flow@^7.7.4":
   version "7.7.4"
   resolved "https://registry.yarnpkg.com/@babel/plugin-syntax-flow/-/plugin-syntax-flow-7.7.4.tgz#6d91b59e1a0e4c17f36af2e10dd64ef220919d7b"