Is there a new Linuxcnc release in the wings ?

Everything has been pretty well documented within the package lists and in the commit messages.

I thought a backport would be a package that is in eg Trixie that was been repackaged for Bookworm.

TBH the extra packages may be pulling in too much extra stuff, the ISO weighs in at about 4.1G, which I think is due to suggested packages being installed as well. And TBH I've only included them to make transferring files around a little easier whilst testing. Like I said it's experimentation ATM, whether it's any use upstream I don't know.

Not even going to bother to upload to Google drive and ask for any help testing as it was a waste of time. I guess people are busy.

Is this the Machine Kit you refer to:

www.machinekit.io/

Yes.

The mk mailing list just receives spam, I haven't seen any actual activity for a while.
The Github repos, even the repos that they split, (long story if you want more info on that you will have to read the repos), haven't had any activity for a long time.

Agreed; so much good code goes to waste; at least it's open source!

Dead proprietary programs just go to waste.