diff --git a/install/install.sql b/install/install.sql
index 5282c685..66fe0d65 100644
--- a/install/install.sql
+++ b/install/install.sql
@@ -1,4 +1,4 @@
 -- Migrate from plugin version 2, if any
 UPDATE plugins SET enabled = 'no' WHERE pluginclassname = 'OpenCast';
-INSERT IGNORE INTO schema_version (domain, branch, version) SELECT 'OpencastV3' as domain, branch, version FROM schema_version WHERE domain = 'OpenCast';
-UPDATE schema_version SET version = 0 WHERE domain = 'OpenCast';
+REPLACE INTO schema_version (domain, branch, version) SELECT 'OpencastV3' as domain, branch, version FROM schema_version WHERE domain = 'OpenCast';
+
diff --git a/migrations/096_fix_v3.php b/migrations/096_fix_v3.php
index 46871051..8ebe96c2 100644
--- a/migrations/096_fix_v3.php
+++ b/migrations/096_fix_v3.php
@@ -24,7 +24,9 @@ public function up()
 
         // fix tool activations and plugin activations
         $old_plugin_id = $db->query("SELECT pluginid FROM plugins WHERE pluginclassname = 'OpenCast'")->fetchColumn();
-        $new_plugin_id = $db->query("SELECT pluginid FROM plugins WHERE pluginclassname = 'OpencastV3'")->fetchColumn();
+
+        // guess new plugin id
+        $new_plugin_id = $db->query("SELECT MAX(pluginid) FROM plugins")->fetchColumn() + 1;
 
         if (!empty($old_plugin_id) && !empty($new_plugin_id)) {
             $stmt = $db->prepare("UPDATE tools_activated SET plugin_id = ':new' WHERE plugin_id = ':old'");
@@ -40,10 +42,12 @@ public function up()
             ]);
         }
 
-        // clear cache for autoloader classes
+        // Clear the whole Stud.IP cache to make the plugin work correctlu
         $cache     = StudipCacheFactory::getCache();
-        $cache_key = 'STUDIP#autoloader-classes';
-        $cache->expire($cache_key);
+        $cache->flush();
+
+        // disable migrations for old plugin to prevent accidential deletion of oc-data
+        $db->exec("DELETE FROM schema_version WHERE domain = 'OpenCast'");
     }
 
     public function down()