diff --git a/application/libraries/PrestudentLib.php b/application/libraries/PrestudentLib.php
index 561b19fd4..a57533da0 100644
--- a/application/libraries/PrestudentLib.php
+++ b/application/libraries/PrestudentLib.php
@@ -687,9 +687,6 @@ class PrestudentLib
 		$now = date('c');
 		$today = date('Y-m-d');
 
-		$jahr = mb_substr($studiensemester_kurzbz, 4, 2);
-
-
 		// Genererate Personenkennzeichen
 		$personenkennzeichen = $this->_ci->StudentModel->generateMatrikelnummer2(
 			$student_data->studiengang_kz,
@@ -699,8 +696,9 @@ class PrestudentLib
 		if (isError($personenkennzeichen))
 			return $personenkennzeichen;
 		$personenkennzeichen = getData($personenkennzeichen);
-		
-		
+
+		$jahr = mb_substr($personenkennzeichen, 0, 2);
+
 		// Generate UID
 		$uid = $this->_ci->StudentModel->generateUID(
 			$student_data->kurzbz,
diff --git a/application/models/crm/Student_model.php b/application/models/crm/Student_model.php
index 6f2404cbd..ca9cfe4c3 100644
--- a/application/models/crm/Student_model.php
+++ b/application/models/crm/Student_model.php
@@ -169,7 +169,7 @@ class Student_model extends DB_Model
 
 		$max = 0;
 		if ($matrikelnrres && hasData($matrikelnrres)) {
-			$max = mb_substr(getData($matrikelnrres)[0]->matrikelnr, 7);
+			$max = mb_substr(trim(getData($matrikelnrres)[0]->matrikelnr), -3);
 			if (!is_numeric($max)) {
 				$max = (int)$max;
 			}
diff --git a/cis/testtool/login.php b/cis/testtool/login.php
index 5a2ae0dea..5306dadab 100644
--- a/cis/testtool/login.php
+++ b/cis/testtool/login.php
@@ -447,14 +447,6 @@ if (isset($_POST['save']) && isset($_SESSION['prestudent_id']))
 		{
 			e.preventDefault();
 		});
-		// If Browser is any other than Mozilla Firefox and the test includes any MathML,
-		// show message to use Mozilla Firefox
-		var ua = navigator.userAgent;
-		if ((ua.indexOf("Firefox") > -1) == false)
-		{
-			$("#alertmsgdiv").html("<div class='alert alert-danger'>BITTE VERWENDEN SIE DEN MOZILLA FIREFOX BROWSER!<br>(Manche Prüfungsfragen werden sonst nicht korrekt dargestellt.<br><br>PLEASE USE MOZILLA FIREFOX BROWSER!<br>(Otherwise some exam items will not be displayed correctly</div>");
-			//alert('BITTE VERWENDEN SIE DEN MOZILLA FIREFOX BROWSER!\n(Manche Prüfungsfragen werden sonst nicht korrekt dargestellt.\n\nPLEASE USE MOZILLA FIREFOX BROWSER!\n(Ohterwise some exam items will not be displayed correctly.)');
-		}
 	});
 	</script>
 <?php
diff --git a/cis/testtool/menu.php b/cis/testtool/menu.php
index 7c8b12b9d..7cb6f138d 100644
--- a/cis/testtool/menu.php
+++ b/cis/testtool/menu.php
@@ -425,28 +425,6 @@ else
 			e.preventDefault();
 		});
 	});
-    // Get users Browser
-    var ua = navigator.userAgent;
-
-    // If Browser is any other than Mozilla Firefox and the test includes any MathML,
-    // show message to use Mozilla Firefox
-    if ((ua.indexOf("Firefox") > -1) == false)
-    {
-        let hasMathML = "<?php echo (isset($gebiet_hasMathML)?$gebiet_hasMathML:''); ?>";
-        let userLang = "<?php echo $sprache_user; ?>";
-        if (hasMathML == true)
-        {
-            if (userLang == 'German')
-            {
-                alert('BITTE VERWENDEN SIE DEN MOZILLA FIREFOX BROWSER!\n(Manche Prüfungsfragen werden sonst nicht korrekt dargestellt.)');
-            }
-            else if(userLang == 'English')
-            {
-                alert('PLEASE USE MOZILLA FIREFOX BROWSER!\n(Ohterwise some exam items will not be displayed correctly.)');
-            }
-        }
-    }
-
     // Error massage if check_gebiet function returns false
     $(function() {
         var invalid_gebiete = "<?php echo (isset($invalid_gebiete)?$invalid_gebiete:''); ?>";