Upgrade from 4.4-8 to 5.0-0 fails due to appliance.json

Hey everyone,
Looking for some guidance on this as trying to push the update.
OwnCloud is the only app package running on the server, running the latest release 10.7.0; which is supported for UCS 5.0-0

Starting pre-update-checks-5.0-0 (Wed Jun 9 08:27:51 MST 2021):
Checking adc_mapping … OK
Checking adc_multiinstance_mapping … OK
Checking architecture … OK
Checking blocking_apps … Unable to cache apps
Unable to cache apps
OK
Checking default_master_packages … OK
Checking disk_space … OK
Checking failed_ldif … OK
Checking for_postgresql94 … OK
Checking hold_packages … OK
Checking kolab_schema … OK
Checking ldap_connection … OK
Checking ldap_schema … OK
Checking legacy_objects … OK
Checking master_version … OK
Checking md5_signature_is_used … OK
Checking min_version … OK
Checking minimum_ucs_version_of_all_systems_in_domain … OK
Checking old_packages … OK
Checking overwritten_umc_templates … OK
Checking ox_schema … OK
Checking package_status … OK
Checking python_ucr_template_compatibility … FAIL
Checking role_package_removed … OK
Checking samba_server_schannel … OK
Checking samba_tdb_size … OK
Checking slapd_on_member … OK
Checking system_date_too_old … OK
Checking system_role … OK
Checking tls_public_key_size … OK
Checking tls_public_key_size_ucs-sso … OK
Checking usr_mountpoint … OK
Checking valid_machine_credentials … OK

The system can not be updated to UCS 5.0 due to the following reasons:

python_ucr_template_compatibility:
The following UCR templates are not compatible with Python 3:
/etc/univention/templates/files/usr/share/univention-web/js/umc/hooks/appliance.json (package: univention-app-appliance)