I got an update notice for the Apple Mail integrated GPG tools. After the update you get a modal dialog in Apple Mail telling you that you now need a subscription to continue using the product. This was poorly planned and people are complaining.
https://gpgtools.tenderapp.com/discussions/feedback/11880-support-plan
Bad title. Title should be "Apple Mail GPG Tools ..." because this concerns Apple Mail's tools, not GPG itself.
GPGTools tried this before. The backlash was substantial.