Andrew Owen posted a brief update about his latest work on U3.5: Pax Britannia to the Ultima Dragons Facebook group. It doesn’t mention much about any advancements made on the game proper. Instead, it focuses on the tools that Andrew is using to build the game:

I’ve been doing a bit of work on the IDE for the ZXodus][Engine. Most of the tools I’m using are freely available for Windows. But I’m a Mac user, so I’ve bundled them together in a Wineskin Wine wrapper. This way I can keep the entire project and tools self contained. The icons represent the graphics editor, map editor, music editor, sound effects editor, script editor, and project builder.

You can see all of the icons pictured above, albeit somewhat blown up from what I assume is their native resolution.