Making announcement and having all MongoDB Community Software change license the same day for all current major versions (not just new major releases) is not very friendly to users of such software
Many companies which are serious about their software licenses will need to evaluate whenever they can use SSPL, in the meanwhile being left without access to security updates... not a good place to be.
Though I suspect MongoDB would just like such companies to use Commercially Licensed Enterprise Version and not deal with all these Open Source (or not) license change
Advance Submission to OSI and validating it as Open Source License would reduce the concerns of companies looking to use MongoDB Community as they could rely on OSI's legal analyses rather than perform their own