diff --git a/lib/db/mysql.php b/lib/db/mysql.php
index b5cb9775564..90eb2209cad 100644
--- a/lib/db/mysql.php
+++ b/lib/db/mysql.php
@@ -716,6 +716,11 @@ function main_upgrade($oldversion=0) {
         }
     }
 
+    if ($oldversion < 2004030701) {     /// Because of the renaming of Czech language pack
+        modify_database("", "UPDATE prefix_user SET lang = 'cs' WHERE lang = 'cz'");
+        modify_database("", "UPDATE prefix_course SET lang = 'cs' WHERE lang = 'cz'");
+    }
+
     return $result;
 
 }
diff --git a/lib/db/postgres7.php b/lib/db/postgres7.php
index 30969d17383..7785b6abd9c 100644
--- a/lib/db/postgres7.php
+++ b/lib/db/postgres7.php
@@ -461,6 +461,11 @@ function main_upgrade($oldversion=0) {
         }
     }
 
+    if ($oldversion < 2004030701) {     /// Because of the renaming of Czech language pack
+        modify_database("", "UPDATE prefix_user SET lang = 'cs' WHERE lang = 'cz'");
+        modify_database("", "UPDATE prefix_course SET lang = 'cs' WHERE lang = 'cz'");
+    }
+
     return $result;
 
 }
diff --git a/version.php b/version.php
index d6d0da71336..975b415b400 100644
--- a/version.php
+++ b/version.php
@@ -5,7 +5,7 @@
 // database to determine whether upgrades should
 // be performed (see lib/db/*.php)
 
-$version = 2004030700;   // The current version is a date (YYYYMMDDXX)
+$version = 2004030701;   // The current version is a date (YYYYMMDDXX)
 
 $release = "1.2 Beta +";   // User-friendly version number