I tried to return to 3.4.8, but nothing has changed.
What do you mean by this? Are you able to boot 3.4.8?
My computer dont see new release (3.5.3), what i need to do?
Open the App Center, go to Updates, and click the “refresh” button in the corner. After a while, the 3.5.3 update should be offered. If not, please generate a debug log following these instructions: