In the past Flarm had two types of Updates, MINOR and MAJOR.

MINOR update (X.06) generally covered smaller enhancements and bugfixes. A lot of these concerned small glitches in third party devices effecting only few users. In most cases these updates could be ignored, because they did not effect your device or concerned non essential feature additions. Often major releases were accomponied with multiple ensuing minor versions to fix previously undetected bugs.

MAJOR updates (6.XX) were/are the mandatory updates. These included changes to the communication protocoll and/or major changes to the collision avoidance algorithm. Major updates were planned to fixed dates years in advance and strictly mandatory. Flarm chose this update scheme because it allowed full flexibility in improving the software at minimal effort, because it was not necessary ensure compatibility to obsolete software versions. This update scheme was one of the major success factors for Flarm, because it facilitated a steep development curve while keeping cost low. The unfortunate drawback is that it is not the most user friendly approach.

After a lot of user complaints Flarm decided to change the update scheme last year. Instead of mandatory release dates at changing intervals and explaining about major and minor versions, they simplfied things to one easy to understand message: "Dear pilot, download a current Flarm version once a year and do the update. Don't bother with version details or compatibility - we will take care of everything else."

As I understand the new update scheme, no more big bang major updates are planned. Possibly Flarm software has matured sufficiently so that non compatible big bang major versions are no longer needed. Maybe they have found more elegant time triggered ways to implement compatibility related updates across the fleet within the current rolling update scheme. Incase the need for a new big bang major version becomes apparent, necessary provisons (new big bang date) can be reintroduced via the current update scheme within 365 days. I expect Flarm will try to avoid this in the future, because it is usually accompanied by a wave of user upsets. But, I have to concede, I am only guessing...