Update to 5.0 failsdue unremovable LDAP entries (Kolab)

I am trying to update to UCS 5.0 but the update fails due to the following entries ins LDAP.

Checking minimum_ucs_version_of_all_systems_in_domain ... FAIL
Checking old_packages ...                         OK
Checking overwritten_umc_templates ...            OK
Checking ox_schema ...                            OK
Checking package_status ...                       OK
Checking python_ucr_template_compatibility ...    OK
Checking python_ucsschool_hooks_compatibility ... OK
Checking role_package_removed ...                 OK
Checking samba_server_schannel ...                OK
Checking samba_tdb_size ...                       OK
Checking slapd_on_member ...                      OK
Checking ssh ...                                  OK
Checking system_date_too_old ...                  OK
Checking system_role ...                          OK
Checking term ...                                 OK
Checking tls_public_key_size ...                  OK
Checking tls_public_key_size_ucs-sso ...          OK
Checking ucsschool_computerroom_compatibility ... 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:

minimum_ucs_version_of_all_systems_in_domain:
The following extensions are incompatible with UCS 5.0:
        cn=univention-kolab3,cn=ldapacl,cn=univention,dc=company,dc=de: [unspecified..unspecified)
        cn=hookKolabEnabled,cn=udm_hook,cn=univention,dc=company,dc=de: [unspecified..unspecified)
        cn=kolab-syntax-classes,cn=udm_syntax,cn=univention,dc=company,dc=de: [unspecified..unspecified)

I already tried to delete the entries with the following statement, but it does not delete them.
Output is: “invalid DN”

root@pdc:~# ldapdelete -x -D "cn=admin,$(ucr get ldap/base)" -y /etc/ldap.secret “cn=univention-kolab3,cn=ldapacl,cn=univention,dc=company,dc=de”
ldap_delete: Invalid DN syntax (34)
	additional info: invalid DN

Any Ideas, anyone?