How can I download an older version?
I really liked the version of Opera I was using on my phone until I updated it a few months ago (unfortunately I don't know what version it was), but the newer version is unusable for me. Is there a place I can download previous versions?
Old versions should be on http://arc.opera.com/pub/opera/android/ but it looks like that page hasn't been updated in a very long time as the newest one there is 12.10.
There are also sites dedicated to archiving old versions of Android apps. I don't think it would be appropriate to link to them here but as always in such matters, Google is your friend. Be sure to turn on Verify Apps under Security in the Google Settings apps so that apps from unofficial sources are checked for virii when installing.