Yes, absolutely - the next release is scheduled for June, our current development cycle (which may not be ideal) is based on internal builds and testing before public release. The main reason is that there are e.g. insurance companies out there and whilst well, it's still open-source, we would not like to break anything for them.

Could you merge consistently and just cut stable releases on a scheduled cadence?

Yes, that's a good point - actually we were discussing this option (again!) just last week as we are cautious of not-that-frequent public releases.

Without it any contribution will probably be a pain to handle (and it's usually already not trivial to handle correctly ;).

Curious what testing is covered that you don't have automated as part of the CI?

These are mainly either integration tests with hard-to-automate third-party platforms and tests in more complex multi-tenant deployment scenarios.

There is also the Enterprise version which is developed in parallel with the open-source Core edition. Being a small team we just found it was easier to phase the release schedule.