I have a site running Drupal 8.9.13. I have enabled email notification for "only security updates" and it generally works well - I get a mail for "urgent things" otherwise I wait and apply ordinary updates once a month.
Today I received a warning about an unsupported release. When I check, all I find is an available update. For this module, I am running 2.0.0 and 2.1.0 is available. According to the documentation about semantic versioning for Drupal modules, this is a change to the minor version. I don't see any reason why 2.0.0 is in fact unsupported.
From my perspective, this isn't an "urgent thing" and I don't want to be mailed about it every day. Under the "old" version numbering scheme, a minor version change such as 8.x-3.5 to 8.x-3.6 does not cause the same behaviour.
Is this a bug in the Drupal core update module? Or have I misunderstood how the new semantic version mechanism works?