Opera Mini updates are usually a good thing. They include bug fixes and often, new features. But for a few users, usually with old or obscure phones, the new version doesn't work as well as the old one or work at all. On the Opera Mini User forum there is a recurrent theme of users, trying a released version and insisting that one of older ones, was better.
There's a sticky post on the forum with links to some old versions but it's far from complete and doesn't include beta versions or signed ones.
I can understand Opera wanting users to be on the latest version, but when that version doesn't work it's nice to have the option to roll back to an older one. I've gathered up all the Opera Mini 5 versions I've been able to find and linked to them below.
These are all English language versions. Java phone users should try the JAD link first and if it doesn't work try the JAR.
If you get an expired certificate error installing one of the signed versions, try setting your phone's date back a year or two. Be sure to set the date back to the current one before trying to run Opera Mini to avoid getting a "Verification of server certificate" error.
The ZIP files are for use with BlackBerry Desktop Manager.
I don't have the other signed Java versions or OTA files for BlackBerrys. If and when I find them I will post them here. If any readers have copies of the missing versions and are willing to share them, please leave a comment.
Updated 5-Oct-2012: Originally published in October 2010, this post is still one of the most popular on WAP Review. Today I went through some old download directories and added over a dozen more old Opera Mini versions.
Updated 12-Jul-2013: Added PalmOS PRC version and Palm Java ME JVM