I’m genuinely surprised that a product with an announced end-of-life date is still doing major version releases.
I can only hope that the move from 10 → 11 is much smoother than the jump from 9 → 10 was, both in terms of development/testing (looking at you javax → Jakarta), as well as the ongoing burden of managing multiple builds/releases of our apps targeting each major.
For much of the lifetime of our apps we were able to have one build that worked across Confluence 6.x - 9.x. That ended with v10, and we now publish two version of every release (one for 6.x-9.x, and another for 10.x); and this was further complicated by the new process that requires every new version to go through an automated approval step which adds a minimum of 10-15 minutes to each version published.
If 11.x requires us to add a third build, we’ll have to seriously consider whether it’s worth continuing to offer DC versions given the dwindling expected sales.