diff --git a/README.md b/README.md
index ff9d9d9a1..4d86c0e84 100644
--- a/README.md
+++ b/README.md
@@ -36,50 +36,59 @@ This fork has the following changes:
 * Admin uses password_hash/password_verify
 * Auth failed attempts written to syslog
 * Added Fail2ban instructions
-* ES2015 (removed polyfills and Modernizr)
+* ES2015
 * PHP 7.3+ required
 * PHP mbstring extension required
 * PHP replaced pclZip with ZipArchive
 * PHP yaml extension else use the old Spyc
 * Removed BackwardCapability (class \RainLoop\Account)
 * Removed ChangePassword (plugins won't work)
-* Removed JS nanoscroll, jquery-scrollstop, jquery-mousewheel, matchmedia-polyfill
 * Removed OAuth support
 * Removed POP3 support
 * Removed background video support
 * Removed Sentry (Application Monitoring and Error Tracking Software)
 * Replaced gulp-uglify with gulp-terser
 * CRLF => LF line endings
-* Converted underscore.js to native code
 * Ongoing removal of old JavaScript code (things are native these days)
 
 ### Removal of old JavaScript
 
-This fork uses jQuery.slim, downsized/simplified versions of scripts and has no support for Internet Explorer.
+This fork uses downsized/simplified versions of scripts and has no support for Internet Explorer.
 
 The result is faster and smaller download code (good for mobile networks).
 
 Things might work in Edge 15-18, Firefox 47-62 and Chrome 54-68 due to one polyfill for array.flat().
 
-|js/*       	|1.14.0   	|native   	|
-|-----------	|--------:	|--------:	|
-|admin.js    	|2.130.942	|1.222.392	|
-|app.js      	|4.184.455	|2.984.765	|
-|boot.js     	|  671.522	|   94.230	|
-|libs.js     	|  647.614	|  507.015	|
-|polyfills.js	|  325.834	|        0	|
-|TOTAL js   	|7.960.367	|4.808.402	|
+* Replaced jQuery with jQuery.slim
+* Removed pikaday
+* Removed underscore
+* Removed polyfills
+* Removed Modernizr
+* Removed nanoscroll
+* Removed jquery-scrollstop
+* Removed jquery-mousewheel
+* Removed matchmedia-polyfill
 
-|js/min/*       	|1.14.0   	|native   	|
-|---------------	|--------:	|--------:	|
-|admin.min.js    	|  252.147	|  157.533	|
-|app.min.js      	|  511.202	|  389.339	|
-|boot.min.js     	|   66.007	|   11.575	|
-|libs.min.js     	|  572.545	|  464.161	|
-|polyfills.min.js	|   32.452	|        0	|
-|TOTAL js/min   	|1.434.353	|1.022.608	|
+|js/*       	|1.14.0 	|native 	|gzip 1.14	|gzip   	|
+|-----------	|--------:	|--------:	|--------:	|--------:	|
+|admin.js    	|2.130.942	|1.221.247	|  485.481	|  299.073	|
+|app.js      	|4.184.455	|2.984.765	|  932.725	|  697.869	|
+|boot.js     	|  671.522	|   94.230	|  169.502	|   28.386	|
+|libs.js     	|  647.614	|  507.015	|  194.728	|  153.918	|
+|polyfills.js	|  325.834	|        0	|   71.825	|        0	|
+|TOTAL js   	|7.960.367	|4.807.257	|1.854.261	|1.179.246	|
+
+|js/min/*       	|1.14.0   	|native   	|gzip 1.14	|gzip   	|
+|---------------	|--------:	|--------:	|--------:	|--------:	|
+|admin.min.js    	|  252.147	|  157.523	| 73.657	| 45.136	|
+|app.min.js      	|  511.202	|  389.339	|140.462	|102.945	|
+|boot.min.js     	|   66.007	|   11.575	| 22.567	|  4.461	|
+|libs.min.js     	|  572.545	|  464.161	|176.720	|143.916	|
+|polyfills.min.js	|   32.452	|        0	| 11.312	|      0	|
+|TOTAL js/min   	|1.434.353	|1.022.598	|424.718	|296.458	|
+
+411.755 bytes (128.260 gzip) is not much, but it feels faster.
 
-411.745 bytes is not much, but it feels faster.
 
 |css/*       	|1.14.0   	|native   	|
 |--------------	|--------:	|--------:	|
diff --git a/rainloop/v/0.0.0/app/libraries/MailSo/Sieve/ManageSieveClient.php b/rainloop/v/0.0.0/app/libraries/MailSo/Sieve/ManageSieveClient.php
index 783a4ab54..8e20157fe 100644
--- a/rainloop/v/0.0.0/app/libraries/MailSo/Sieve/ManageSieveClient.php
+++ b/rainloop/v/0.0.0/app/libraries/MailSo/Sieve/ManageSieveClient.php
@@ -215,7 +215,7 @@ class ManageSieveClient extends \MailSo\Net\NetClient
 		foreach ($aResponse as $sLine)
 		{
 			$aTokens = $this->parseLine($sLine);
-			if (false === $aTokens)
+			if (!$aTokens)
 			{
 				continue;
 			}
diff --git a/rainloop/v/0.0.0/app/libraries/RainLoop/ServiceActions.php b/rainloop/v/0.0.0/app/libraries/RainLoop/ServiceActions.php
index c3b9089b4..3cc3c517f 100644
--- a/rainloop/v/0.0.0/app/libraries/RainLoop/ServiceActions.php
+++ b/rainloop/v/0.0.0/app/libraries/RainLoop/ServiceActions.php
@@ -635,7 +635,7 @@ class ServiceActions
 					$sThemeValuesFile = APP_VERSION_ROOT_PATH.'app/templates/Themes/values.less';
 					$sThemeTemplateFile = APP_VERSION_ROOT_PATH.'app/templates/Themes/template.less';
 
-					if (\file_exists($sThemeFile) && \file_exists($sThemeTemplateFile) && \file_exists($sThemeValuesFile))
+					if (\is_file($sThemeFile) && \is_file($sThemeTemplateFile) && \is_file($sThemeValuesFile))
 					{
 						$aResult[] = '@base: "'.
 							($bCustomTheme ? Utils::WebPath() : Utils::WebVersionPath()).
@@ -645,7 +645,7 @@ class ServiceActions
 						$aResult[] = \file_get_contents($sThemeFile);
 						$aResult[] = \file_get_contents($sThemeTemplateFile);
 
-						if (\file_exists($sThemeExtFile))
+						if (\is_file($sThemeExtFile))
 						{
 							$aResult[] = \file_get_contents($sThemeExtFile);
 						}
@@ -1037,7 +1037,7 @@ class ServiceActions
 		$sMomentFileName = APP_VERSION_ROOT_PATH.'app/localization/moment/'.
 			$this->convertLanguageNameToMomentLanguageName($sLanguage).'.js';
 
-		if (\file_exists($sMomentFileName))
+		if (\is_file($sMomentFileName))
 		{
 			$sMoment = \file_get_contents($sMomentFileName);
 			$sMoment = \preg_replace('/\/\/[^\n]+\n/', '', $sMoment);
diff --git a/rainloop/v/0.0.0/app/libraries/RainLoop/UserAgent.php b/rainloop/v/0.0.0/app/libraries/RainLoop/UserAgent.php
index 8eea3a229..05ebc28ee 100644
--- a/rainloop/v/0.0.0/app/libraries/RainLoop/UserAgent.php
+++ b/rainloop/v/0.0.0/app/libraries/RainLoop/UserAgent.php
@@ -150,8 +150,10 @@ class UserAgent
 	public static function getHeader() : string
 	{
 		static $agent;
-		if (null === $agent && isset($_SERVER['HTTP_USER_AGENT'])) {
-			$agent = strtolower(substr($_SERVER['HTTP_USER_AGENT'], 0, 500));
+		if (null === $agent) {
+			$agent = isset($_SERVER['HTTP_USER_AGENT'])
+				? strtolower(substr($_SERVER['HTTP_USER_AGENT'], 0, 500))
+				: '';
 		}
 		return $agent;
 	}
diff --git a/rainloop/v/0.0.0/app/templates/Index.html b/rainloop/v/0.0.0/app/templates/Index.html
index a8af1e87e..3fd0f8b2f 100644
--- a/rainloop/v/0.0.0/app/templates/Index.html
+++ b/rainloop/v/0.0.0/app/templates/Index.html
@@ -22,6 +22,7 @@
 
 <body class="thm-body">
 	<div id="rl-app"></div>
+	<div id="rl-check"></div>
 	<script type="text/javascript" data-cfasync="false" src="{{BaseAppBootScriptLink}}"></script>
 </body>
 
diff --git a/rainloop/v/0.0.0/include.php b/rainloop/v/0.0.0/include.php
index 0444ad6a5..0537eb0d2 100644
--- a/rainloop/v/0.0.0/include.php
+++ b/rainloop/v/0.0.0/include.php
@@ -28,7 +28,7 @@
 
 			define('APP_DEFAULT_PRIVATE_DATA_NAME', '_default_');
 
-			$sPrivateDataFolderInternalName = file_exists(APP_INDEX_ROOT_PATH.'MULTIPLY') ? APP_SITE : '';
+			$sPrivateDataFolderInternalName = is_file(APP_INDEX_ROOT_PATH.'MULTIPLY') ? APP_SITE : '';
 			define('APP_PRIVATE_DATA_NAME', 0 === strlen($sPrivateDataFolderInternalName) ? APP_DEFAULT_PRIVATE_DATA_NAME : $sPrivateDataFolderInternalName);
 			define('APP_MULTIPLY', 0 < strlen($sPrivateDataFolderInternalName) && APP_DEFAULT_PRIVATE_DATA_NAME !== APP_PRIVATE_DATA_NAME);
 
@@ -40,7 +40,7 @@
 			$sCustomDataPath = '';
 			$sCustomConfiguration = '';
 
-			if (file_exists(APP_INDEX_ROOT_PATH.'include.php'))
+			if (is_file(APP_INDEX_ROOT_PATH.'include.php'))
 			{
 				include_once APP_INDEX_ROOT_PATH.'include.php';
 			}
@@ -55,9 +55,9 @@
 
 			define('APP_DATA_FOLDER_PATH_UNIX', str_replace('\\', '/', APP_DATA_FOLDER_PATH));
 
-			$sSalt = file_get_contents(APP_DATA_FOLDER_PATH.'SALT.php');
-			$sData = file_exists(APP_DATA_FOLDER_PATH.'DATA.php') ? file_get_contents(APP_DATA_FOLDER_PATH.'DATA.php') : '';
-			$sInstalled = file_get_contents(APP_DATA_FOLDER_PATH.'INSTALLED');
+			$sSalt = is_file(APP_DATA_FOLDER_PATH.'SALT.php') ? file_get_contents(APP_DATA_FOLDER_PATH.'SALT.php') : '';
+			$sData = is_file(APP_DATA_FOLDER_PATH.'DATA.php') ? file_get_contents(APP_DATA_FOLDER_PATH.'DATA.php') : '';
+			$sInstalled = is_file(APP_DATA_FOLDER_PATH.'INSTALLED') ? file_get_contents(APP_DATA_FOLDER_PATH.'INSTALLED') : '';
 
 			// installation checking data folder
 			if (APP_VERSION !== $sInstalled)
@@ -68,8 +68,8 @@
 				$sCheckFolder = APP_DATA_FOLDER_PATH.$sCheckName;
 				$sCheckFilePath = APP_DATA_FOLDER_PATH.$sCheckName.'/'.$sCheckName.'.file';
 
-				unlink($sCheckFilePath);
-				rmdir($sCheckFolder);
+				is_file($sCheckFilePath) && unlink($sCheckFilePath);
+				is_dir($sCheckFolder) && rmdir($sCheckFolder);
 
 				if (!is_dir(APP_DATA_FOLDER_PATH))
 				{
@@ -136,9 +136,9 @@
 				file_put_contents(APP_DATA_FOLDER_PATH.'index.html', 'Forbidden');
 				file_put_contents(APP_DATA_FOLDER_PATH.'index.php', 'Forbidden');
 
-				if (!file_exists(APP_DATA_FOLDER_PATH.'.htaccess') && file_exists(APP_VERSION_ROOT_PATH.'app/.htaccess'))
+				if (!is_file(APP_DATA_FOLDER_PATH.'.htaccess') && is_file(APP_VERSION_ROOT_PATH.'app/.htaccess'))
 				{
-					file_put_contents(APP_DATA_FOLDER_PATH.'.htaccess', file_get_contents(APP_VERSION_ROOT_PATH.'app/.htaccess'));
+					copy(APP_VERSION_ROOT_PATH.'app/.htaccess', APP_DATA_FOLDER_PATH.'.htaccess');
 				}
 
 				if (!is_dir(APP_PRIVATE_DATA))