Hello,
I faced with interesting project ReOpenLDAP
github.com/ReOpen/ReOpenLDAP
It looks like it can be used as a replacement of OpenLDAP in UCS server.
According to their description, it has a lot of fixes and improvements.
Also there is result of analysis of ReOpenLDAP by PVS-Studio.
viva64.com/en/b/0422/
Perhaps it would help to implement more interesting, useful and stable things.
Thanks for your work and amazing product Univention Corporate Server.