Solved the problem, at least for me, with the radio menu which no longer allowed the 'INBOUND' option from Carrier ATC.
You need to enable the 'allow airboss' option from the carrier properties window in mission editor and communications with Carrier ATC are possible again (you do not need to also enable 'allow LSO').
It therefore seems that Carrier ATC is now linked to enabling the Airboss function. If anyone can verify, so as to confirm and help others. THANKS.
joker62's post in ATC and recording flight time and landings issues (after fix patch 2.9.6.58056) was marked as the answer