The announcements says the discontinuation is because of “the integration of Quickoffice into the Google Docs, Sheets and Slides apps”. But I don’t see any sign of this integration. With the latest Docs app, I can’t open a .docx file from my Google Drive; only Document Viewer and Quickoffice can open it.

Not that I’m too fussed; I never edit documents on mobile anyway. I use styles often, and neither Quickoffice nor Docs on Android support styles (e.g. header styles).