I’d love to see it return too. Thanks for pointing out your interest in it — the more requests we get from Couchbase customers [or potential customers], the more likely it is to be prioritized in a future release.
Support for Android API 19 and 21 is being deprecated in this release and will be removed in a future release. 
At what date will it be removed? Will it be for CBL 3? Any timeline is helpful. I’m asking as I still have end users with API 21 - including in Germany. Feedback I received why people did not upgrade include:
people who lived through the 70s, 80s expect devices to last a decade or more
people who feel buying a newer device as producing waste