No, phonebook is not working (can't be provisioned). You can create a custom Panasonic phonebook (upto 500 entries) and upload it manually in KX-UT phones. I haven't tested with KX-HDV series.
KX-UT templates were available for a short period during v11 or v12, after that were dismissed. I have maintained them and upgraded to v15.5, as I have a very large installed base of KX-UT phones. Here are mines -- change file extension to .xml, before uploading into 3CX:
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