@fbartels If there is a conflicting username, we skip it. It will log a conflict. If it helps, the code is at https://git.cloudron.io/cloudron/box/blob/master/src/externalldap.js#L185
Yes, base container requirement is gone (it was never enforced by the platform itself, but just our buildbot which is gone now).
I would hold on till 4.3.3 to test the LDAP connector.