UI text doesn't scale with 4k.

High DPI support was never added to Wurm Unlimited, but with a little tweaking you can adjust font size to higher resolutions.

NOTE: Adjusting font settings can cause some window buttons to be scaled outside the view of a window. One such case is the Add Role window for a settlement; the Save Role button can't be seen, thus can't be clicked to save the role. If this happens to you, you may have to adjust font size and/or screen resolution.

1. Make sure you don't have Wurm Unlimited running.
2. If you have a shortcut for the Wurm Client executable, right click and select Properties. Otherwise, navigate to the WurmLauncher folder and find WurmLauncher.exe, then right click and select Properties. TIP: You can quickly get to the WurmLauncher folder by going into your Steam Library and right clicking on Wurm Unlimited, then Manage → Browse Local Files. This puts you in the Wurm Unlimited folder. You then go into the WurmLauncher folder where the Wurm Client executable is found.
3. In the Wurm Client executable Properties change to the Compatibility tab.
4. Click the Change High DPI Settings button.
5. Check both checkboxes on the High DPI Settings window and set the lower drop box to System.
6. Click Ok on both windows to accept the new settings.
7. Open the Wurm Client (WurmLauncher.exe) and click on the Settings button (the gear). Go to the Text tab. Modify font settings. Load into the game and test. If you need to make changes, close the game and repeat step 7 until you achieve desired results.

Freth: On Windows with a 4k monitor I prefer to run WU at 1920×1080 with a slight font adjustment. On Linux Mint I use the same resolution with a 100% monitor scale setting (see below).

1. Right click Desktop.
2. Display, Settings, turn on Enable fractional scaling controls (experimental).
3. Go back to Layout tab and set the scaling percentage and test it with the game.

There may be another way through the command line using XRANDR or some other setting. I don't know.