I'm on LOS21 for nearly 2 weeks now. All the Sony apps that worked on LOS 20 work on 21 as well - Photography Pro 1.6.A.0.27, Cinema Pro 1.9.1.A.0.14, Album 9.9.A.0.20. Haven't tried newer versions of the camera apps.
The only thing I miss is the wireless charging of other devices, power share...