diff --git a/doc/errata/staging/univention-directory-manager-modules.yaml b/doc/errata/staging/univention-directory-manager-modules.yaml
new file mode 100644
index 0000000000..46065a4046
--- /dev/null
+++ b/doc/errata/staging/univention-directory-manager-modules.yaml
@@ -0,0 +1,11 @@
+product: ucs
+release: "5.0"
+version: [6]
+scope: ucs_5.0-0-errata5.0-6
+src: univention-directory-manager-modules
+fix: 15.0.25-26
+desc: |
+ This update addresses the following issues:
+ * Compatibility with Python 2.7 has been restored, which was broken by
+   erratum 991.
+bug: [57146]
diff --git a/management/univention-directory-manager-modules/debian/changelog b/management/univention-directory-manager-modules/debian/changelog
index f04d47e193..1c0fd42048 100644
--- a/management/univention-directory-manager-modules/debian/changelog
+++ b/management/univention-directory-manager-modules/debian/changelog
@@ -1,3 +1,9 @@
+univention-directory-manager-modules (15.0.25-26) unstable; urgency=medium
+
+  * Bug #57146: restore Python 2.7 compatibility
+
+ -- Florian Best <best@univention.de>  Thu, 14 Mar 2024 09:06:16 +0100
+
 univention-directory-manager-modules (15.0.25-25) unstable; urgency=low
 
   * Bug #50385: Fix UDM CLI server start
diff --git a/management/univention-directory-manager-modules/modules/univention/admin/modules.py b/management/univention-directory-manager-modules/modules/univention/admin/modules.py
index 839cd52efa..90ac0a0e4d 100644
--- a/management/univention-directory-manager-modules/modules/univention/admin/modules.py
+++ b/management/univention-directory-manager-modules/modules/univention/admin/modules.py
@@ -206,7 +206,7 @@ def _get(module):
     """
     if not modules:
         update()
-    if isinstance(module, str):
+    if isinstance(module, six.string_types):
         return modules[module]
     return module