Every time Gravit updates to a new version, the app is put in maintenance mode when the build proccess is started. The build ends when ALL browsers and desktop apps for all platforms are ready (which takes time, as expected of a multiplatform app), and only then we take Gravit out of the maintenance mode.
Right now Gravit is just being updated to version 2019-1.3, and it’s as simple as that. Only difference is that now we introduced this maintenance mode screen to explain that. Nothing’s been hacked.