In the process of working through the files detailed in the previous post, I made the following changes to the Apparatus app:

Added some proper error handling for the condition where the template.xml file is not found. Previously, this would prevent the app from saving data, but now it can just save a text file in place of the full XML file, so there's less risk of data loss if the template file is missing.

Built a manifest file to include version info in the package. However, I'm not sure whether this is done correctly, and whether it's actually working. The info on this is sparse.

Tested on Ubuntu again, just to make sure the app remains portable after recent rebuilding of the GUI.