Hi @Paolo 
Long time no see!
Yes, we’ve spent the last 9 months or so advising users about this and back in October or November we emailed every user of Classic to let them know of the plan.
Just a couple of things to note from piece that Conor linked to:
On July 1, 2020 , you will no longer be able to edit your projects on Thunkable Classic.
If you have projects that you want to keep, we recommend that before July 1, 2020 you:
- Rebuild your apps in Thunkable X. You can update an app published to the Play Store by importing your keystore feature on Thunkable X
- Export your .aia and import it into a compatible platform like MIT App Inventor
Since November Thunkable X has a better feature set than Thunkable Classic,
And in the last 3 months alone we’ve launched the ability to save screens, the ability to publish as a web app (which means that a single Thunkable X can be published as an Android app, an iOS app and a Web app) and two new Data Viewer Components which allow you to turn a sheet or table of data directly into an app.
If you have any specific apps in Classic that you’d like help migrating to X then we’re more than happy to help you out with this too.