Is Opera Mini still provided?
I've been given a BenQ-Siemens E71 phone with Opera Mini v4-something. Is this version the latest? Was there any undesirable change (like Presto->webkit) about Opera Mini? Which version would you recommend?
What type of system does that phone run? There are certainly later versions of Mini, but not knowing for sure what to look for I can't say if they would work on your phone.
Only mention I see of Siemens mentions s60 version 1.x and is 10 years old, hopefully yours is more recent than that …
The one already installed there is a *.jar (or *.jad) file.
What an OS is there - I do not know, but it is not a Symbian.
Looks like this is the answer - v8.
Jar or jad files are Java applications, so yes you should be able to use version 8. Some old S60 phones that didn't support Java are stuck at version 3.x …
If it's similar to my Siemens M75, then Opera Mini v.4 is the latest that runs on it. Same for my Sony-Ericsson W200. I have tried v.5 but it's unworkable with those screens and other resources. Keep v.4.