diff --git a/apps/dav/lib/Migration/RemoveClassifiedEventActivity.php b/apps/dav/lib/Migration/RemoveClassifiedEventActivity.php
index ad840d8100..1829f57237 100644
--- a/apps/dav/lib/Migration/RemoveClassifiedEventActivity.php
+++ b/apps/dav/lib/Migration/RemoveClassifiedEventActivity.php
@@ -127,6 +127,6 @@ class RemoveClassifiedEventActivity implements IRepairStep {
 
 	protected function getPrincipal(string $principalUri): string {
 		$uri = explode('/', $principalUri);
-		return $uri[2];
+		return array_pop($uri);
 	}
 }