diff --git a/src/serverlib/3rdparty/SabreDAV/vendor/sabre/dav/lib/DAV/StringUtil.php b/src/serverlib/3rdparty/SabreDAV/vendor/sabre/dav/lib/DAV/StringUtil.php
index 10eeceb..e6699b7 100644
--- a/src/serverlib/3rdparty/SabreDAV/vendor/sabre/dav/lib/DAV/StringUtil.php
+++ b/src/serverlib/3rdparty/SabreDAV/vendor/sabre/dav/lib/DAV/StringUtil.php
@@ -81,7 +81,7 @@ class StringUtil {
         $encoding = mb_detect_encoding($input, ['UTF-8', 'ISO-8859-1'], true);
 
         if ($encoding === 'ISO-8859-1') {
-            return utf8_encode($input);
+            return mb_convert_encoding($input, 'UTF-8', 'ISO-8859-1');
         } else {
             return $input;
         }
diff --git a/src/serverlib/3rdparty/SabreDAV/vendor/sabre/http/lib/functions.php b/src/serverlib/3rdparty/SabreDAV/vendor/sabre/http/lib/functions.php
index 1ec123f..520d7ee 100644
--- a/src/serverlib/3rdparty/SabreDAV/vendor/sabre/http/lib/functions.php
+++ b/src/serverlib/3rdparty/SabreDAV/vendor/sabre/http/lib/functions.php
@@ -431,13 +431,8 @@ function decodePath($path) {
 function decodePathSegment($path) {
 
     $path = rawurldecode($path);
-    $encoding = mb_detect_encoding($path, ['UTF-8', 'ISO-8859-1']);
-
-    switch ($encoding) {
-
-        case 'ISO-8859-1' :
-            $path = utf8_encode($path);
-
+    if (!mb_check_encoding($path, 'UTF-8') && mb_check_encoding($path, 'ISO-8859-1')) {
+        $path = mb_convert_encoding($path, 'UTF-8', 'ISO-8859-1');
     }
 
     return $path;
diff --git a/src/serverlib/3rdparty/SabreDAV/vendor/sabre/vobject/lib/StringUtil.php b/src/serverlib/3rdparty/SabreDAV/vendor/sabre/vobject/lib/StringUtil.php
index 1ecb6d1..5d52cd9 100644
--- a/src/serverlib/3rdparty/SabreDAV/vendor/sabre/vobject/lib/StringUtil.php
+++ b/src/serverlib/3rdparty/SabreDAV/vendor/sabre/vobject/lib/StringUtil.php
@@ -43,14 +43,12 @@ class StringUtil {
 
         switch($encoding) {
             case 'ISO-8859-1' :
-                $newStr = utf8_encode($str);
+                //$newStr = utf8_encode($str);
+                $newStr = mb_convert_encoding($str, 'UTF-8', 'ISO-8859-1');
                 break;
-            /* Unreachable code. Not sure yet how we can improve this
-             * situation.
             case 'WINDOWS-1252' :
-                $newStr = iconv('cp1252', 'UTF-8', $str);
+                $newStr = mb_convert_encoding($str, 'UTF-8', 'WINDOWS-1252');
                 break;
-             */
             default :
                  $newStr = $str;