diff --git a/backend/src/Squidex/Areas/Api/Controllers/Apps/AppLanguagesController.cs b/backend/src/Squidex/Areas/Api/Controllers/Apps/AppLanguagesController.cs
index 8e2d441f2..96e1b166a 100644
--- a/backend/src/Squidex/Areas/Api/Controllers/Apps/AppLanguagesController.cs
+++ b/backend/src/Squidex/Areas/Api/Controllers/Apps/AppLanguagesController.cs
@@ -112,6 +112,7 @@ namespace Squidex.Areas.Api.Controllers.Apps
         /// <param name="language">The language to delete from the app.</param>
         /// <returns>
         /// 200 => Language deleted.
+        /// 400 => Language is master language.
         /// 404 => Language or app not found.
         /// </returns>
         [HttpDelete]
diff --git a/backend/src/Squidex/Program.cs b/backend/src/Squidex/Program.cs
index d47479211..ebb6922a1 100644
--- a/backend/src/Squidex/Program.cs
+++ b/backend/src/Squidex/Program.cs
@@ -69,10 +69,11 @@ namespace Squidex
                         {
                             serverOptions.Listen(
                                 IPAddress.Any,
-                                context.Configuration.GetValue<int>("devMode:port"),
-                                listenOptions => listenOptions.UseHttps("../../../local_certs/squidex-dev.pfx", "password"));
+                                5001,
+                                listenOptions => listenOptions.UseHttps("../../../dev/squidex-dev.pfx", "password"));
                         }
                     });
+
                     builder.UseStartup<Startup>();
                 });
     }
diff --git a/backend/src/Squidex/appsettings.json b/backend/src/Squidex/appsettings.json
index a3ad53a46..f74ed02af 100644
--- a/backend/src/Squidex/appsettings.json
+++ b/backend/src/Squidex/appsettings.json
@@ -1,9 +1,4 @@
 {
-  "devMode": {
-    "enable": false,
-    "port": 5001
-  },
-
   "mode": {
     /*
      * Use this flag to set Squidex to readonly, e.g. when you deploy a second instance for migration.
diff --git a/local_certs/create-cert.ps1 b/dev/create-cert.ps1
similarity index 100%
rename from local_certs/create-cert.ps1
rename to dev/create-cert.ps1
diff --git a/local_certs/install-cert.ps1 b/dev/install-cert.ps1
similarity index 100%
rename from local_certs/install-cert.ps1
rename to dev/install-cert.ps1
diff --git a/local_certs/squidex-dev.cer b/dev/squidex-dev.cer
similarity index 100%
rename from local_certs/squidex-dev.cer
rename to dev/squidex-dev.cer
diff --git a/local_certs/squidex-dev.crt b/dev/squidex-dev.crt
similarity index 100%
rename from local_certs/squidex-dev.crt
rename to dev/squidex-dev.crt
diff --git a/local_certs/squidex-dev.pfx b/dev/squidex-dev.pfx
similarity index 100%
rename from local_certs/squidex-dev.pfx
rename to dev/squidex-dev.pfx
diff --git a/frontend/app-config/webpack.config.js b/frontend/app-config/webpack.config.js
index 52f127c70..6ca13d48f 100644
--- a/frontend/app-config/webpack.config.js
+++ b/frontend/app-config/webpack.config.js
@@ -10,14 +10,6 @@ function root() {
     return path.join.apply(path, [appRoot].concat(newArgs));
 };
 
-function tryGetFile(file) {
-    try {
-        return fs.readFileSync(path.resolve(__dirname, file));
-    } catch (ex) {
-        return undefined;
-    }
-}
-
 const plugins = {
     // https://github.com/webpack-contrib/mini-css-extract-plugin
     MiniCssExtractPlugin: require('mini-css-extract-plugin'),
@@ -218,10 +210,6 @@ module.exports = function (env) {
             headers: {
                 'Access-Control-Allow-Origin': '*'
             },
-            https: {
-                 key: tryGetFile('localhost-key.pem'),
-                cert: tryGetFile('localhost.pem'),
-            },
             historyApiFallback: true,
         }
     };
@@ -284,7 +272,11 @@ module.exports = function (env) {
 
         config.plugins.push(
             new plugins.HtmlWebpackPlugin({
-                template: 'app/_theme.html', hash: true, chunksSortMode: 'none', filename: 'theme.html'
+                filename: 'theme.html',
+                hash: true, 
+                chunks: [],
+                chunksSortMode: 'none', 
+                template: 'app/_theme.html'
             })
         );
 
diff --git a/frontend/package.json b/frontend/package.json
index ff44b2eba..ce3d5b01a 100644
--- a/frontend/package.json
+++ b/frontend/package.json
@@ -5,7 +5,7 @@
   "license": "MIT",
   "repository": "https://github.com/SebastianStehle/Squidex",
   "scripts": {
-    "start": "webpack-dev-server --config app-config/webpack.config.js --inline --port 3000 --hot --https --pfx ../local_certs/squidex-dev.pfx --pfx-passphrase password",
+    "start": "webpack-dev-server --config app-config/webpack.config.js --inline --port 3000 --hot --https --pfx ../dev/squidex-dev.pfx --pfx-passphrase password",
     "test": "karma start",
     "test:coverage": "karma start karma.coverage.conf.js",
     "test:clean": "rimraf _test-output",