I have Opera Next installed, just to make sure the new and inferior version doesn't pollute my main browser. It also allows me to keep track of changes to see if there's any chance of migrating to it yet. Opera is slooowly adding features to it so it may eventually approach usefulness, but I'm generally a huge naysayer on this. Notes alone is a blow to lose, it's such a super-quick way to copy in boilerplate text or links I have saved - right click and pick the note.
But try installing Opera Next. That gives you the bleeding edge version and the last good version 12.16 side by side.