Currently thumbnail generation is tied to the Qt version. This is because we use KPluginMetadata for listing available plugins.

That's not good because we would need to ship every thumbnailer in two versions.

The good thing is the actual generation happens out-of-process in kioworker.

Possible solutions:

• Port listing available thumbnailers away from KPluginMetaData so that it doesn't discard plugins with wrong Qt version
• Do what @davidedmundson suggested and adopt Gnome's desktop-file based thumbnailer solution