Hey @DDeka,
the question is why it’s a public app if it’s not listed in the HS Marketplace in first place.
If it’s a company internal app, a private app (now Project app) might have done the job as well.
I’d say, that without a bit more details on how the app works and what it does (a brief overview should be enough) it’s quite hard to say if this message affects you or not. I think it won’t affect you.
In terms of timeline - here’s a community topic of @evaldas and @SteveHTM discussing this topic.
Hope this helps
best,
Anton