if v30/31 is installed already, unrooted phones won't you allow to downgrade without adb
I signed into my Opera account to sync my bookmarks and then uninstall the new version before installing v29.
@leocg APKmirror is run by Android Police, one of the most respected Android site on the web. The download page even provide confirmation that the apk is signed by Opera so it's safe to install.
I've been using Opera since v5, when it was still shareware. I was disappointed when Opera move to Blink engine and dropped most of the features that made it stand out. Although I still use the latest Opera for Windows on my netbook, this latest development of pushing ads onto users of Opera Mini is the last straw. I don't see myself using Opera past the next 12 months. Thanks to all who have put in the hard work to make this great piece of software. Too bad, corporate greed from above ruined your hardwork.