As the first major web browser to reach a double-digit version, Opera has been testing out alpha releases of version 10 for months now. One of the early problems they encountered was bad browser detection scripts that only looked at the first digit of a version number and decided that Opera 10 was actually Opera 1, and therefore too old to handle modern web pages.
After extensive testing, they’ve concluded that the best way to work around this is to pretend to be Version 9.80. From now on, all versions of Opera will identify themselves as “Opera/9.80” with the real version appearing later in the user-agent string.
Opera/9.80 (Macintosh; Intel Mac OS X; U; en) Presto/2.2.15 Version/10.00
This is similar to the way all Gecko-based browsers identify themselves as Mozilla/5.0, then list the real browser name and version number later on, which makes me wonder why they didn’t just stick with that increasingly irrelevant prefix — though I suppose any scripts looking specifically for Opera versions might have still picked up Opera/10 later on in the ID.
It’ll be some time before Firefox or Safari runs into this issue, but with Internet Explorer 8 in wide release, you have to wonder…what will Microsoft do when they get to IE 10?