Andrew Owen posted an update, to the Ultima Dragons Facebook group, on the development status of U3.5: Pax Britannia. Things have been progressing quite well, it would seem:

U3.5:PB update. Have decided to keep the party size down to avoid combat becoming overly tedious (and also because of the smaller view window) so it will be a maximum of six in a party, as per Ulitma V. I’ve sorted out a beta version of the party file format which should be good enough for me to finish the character generator but leaves plenty of room for further expansion. The scripting engine is working out nicely so the game logic can be written in something close to classic BASIC. The next step is to finish the updated character generator, which I hope to have done before the end of the year. Then it’s the long slog to finish coding the game engine. The plot is written, the NPCs chosen, and the map data complete. I still need to port the audio files into the native format and write the dialog trees. Fortunately the coding breaks down nicely into modules so I’ll simply code one at a time and if I get stuck or bored I can switch to another module. I have less free time to work on the project now, but I’ll keep plugging away until it’s done.

If you haven’t already, check out the re-done soundtrack pieces for Pax Britannia that Andrew released a little while back.