Hello!
This is Git where HE is live. [
github.com]
As we can see at now moment, there is only for UE 5.0.
I'm yesterday install UE 5.1 and looking forward for HE compatible plugin.
I think, plugin for 5.1 will be come soon, maybe on next week.
For every UE new version it is always need some time for build and tests new version of plugin.
And this "rule" applies not only to the Houdini plugin.