IBM updated the Technote 7018591 (Detailed System Requirements - Sametime Standard 8.5.1 Windows) in the past and added Domino 8.5.2 now.
So according to the technote Domino 8.5.2 is now supported as:
- Directory Server
- LDAP Server
- Web Server
in combination with Sametime 8.5.1.1.