--- a/ucs-school-lib/python/__init__.py	
+++ a/ucs-school-lib/python/__init__.py	
@@ -31,4 +31,8 @@ 
 # /usr/share/common-licenses/AGPL-3; if not, see
 # <http://www.gnu.org/licenses/>.
 
+import univention.admin.modules as udm_modules
+
+udm_modules.update()  # for school_ldap and models/
+
 from ucsschool.lib.schoolldap import *
--- a/ucs-school-lib/python/models/__init__.py	
+++ a/ucs-school-lib/python/models/__init__.py	
@@ -30,10 +30,6 @@ 
 # /usr/share/common-licenses/AGPL-3; if not, see
 # <http://www.gnu.org/licenses/>.
 
-import univention.admin.modules as udm_modules
-
-udm_modules.update()
-
 from ucsschool.lib.models.school import *
 from ucsschool.lib.models.user import *
 from ucsschool.lib.models.group import *
--- a/ucs-school-lib/python/schoolldap.py	
+++ a/ucs-school-lib/python/schoolldap.py	
@@ -54,9 +54,6 @@ 
 from univention.management.console.modules.decorators import sanitize
 from univention.management.console.modules.sanitizers import StringSanitizer
 
-# load UDM modules
-udm_modules.update()
-
 __bind_callback = None
 
 _ = Translation('python-ucs-school').translate