I have the same problem on iPad, latest version of Evernote. New notes on iPad were not uploaded, edits to existing notes on other devices were not synchronized. I filed a support request and pointed to this thread. Support noted that it will be a few weeks before anyone can reply to my question.
Uninstall and reinstall of the app restores normal functionality, but did NOT recover notes. Especially after uninstall I would assume those notes are forever lost. So don't do that if you need to keep those notes.