To all I know, the update was indeed released yesterday, earlier than originally promised.
I read, some systems take a while to load the whole list of stations, and search on the older platforms is not as powerful as on the new ones.
If you have questions to (missing) stations, Naim have gathered feedback since launching the new services on this thread: https://community.naimaudio.com/t/new-naim-internet-radio-feedback-requests-part-4/