Still need to use "ConverterVersion" even without subscenes?

For Tiny all data is converted to an entities binary file which encapsulates a subscene, or a subscene section. Previously Tiny required all content to be put into a subscene explicitly to allow the data export to serialize the content. This was an unnecessary however so we've removed that requirement and instead treat the overall Unity scene as a subscene. This allows us to serialize content without forcing users to use subscenes when dividing content on disk for loading purposes isn't necessary for the game. You can still use subscenes if you'd like to break up how content is persisted on disk for incremental web downloads or content streaming though.

Hope this helps shed some light on the export. The data export still goes through a conversion step which is why your attribute change is necessary when yo uwant to signal that the export process has changed and content should be re-exported. We just run that process on a "root" subscene that mirrors the Unity Scene.