Hi, we just released tk-houdini v1.9.10 which adds the support for Houdini 21.0.
No need for custom branch anymore! I will remove the custom branches listed in this thread by the end of the month.
Regarding the missing FPT menu, the implemented solution (provided by the SideFx support) only works fir Houdini version 21.0.479+
Please let us know if you see any more issues.
Thanks!