In order to make UI modding available, we have had to update the handling of the ui.xml file. In 3.20 your ui.xml file used a patch facility to hook into the UI system. In 3.50 your ui.xml file is now directly interpreted by the UI engine.
Here's a quick example on how to convert the 3.20 ui.xml file to a matching 3.50 one:
pre 3.50 ui.xml file
post 3.50 ui.xml file
line 2: ensure the name attribute is set to your own addon's name
line 4: add the dependency to the Egosoft addon, you hook into
XPL and Lua byte code support removed
If you provided your scripts in byte code or with a file extension other than ".lua" (for instance ".xpl"), you will have to rename the file and provide the Lua script in plain-text.
Note that this also works in versions prior to 3.50. So if you provided the Lua scripts already with these specifications for 3.20, there's no need to change anything.