Opera User Agent: Opera or OPR?

Question

Most specialized sites mention that Opera user agents all contain the word 'Opera'.

This kinda old post from an Opera developer mentions the string 'OPR' instead.

The point is: my site receives regularly visits from 'OPR' browsers and none from 'Opera'.

Example this morning:

Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/47.0.2526.73 Safari/537.36 OPR/34.0.2036.42

Passing my visitors' UA strings to a couple of online UA analyzers returned the verdict that 'OPR' is plain Chrome.

Can anyone confirm whether real Opera browsers have 'Opera' in their user agent?

Answer 1

According to http://www.useragentstring.com/pages/Opera/ Opera uses Opera. But that's only for versions until 12.
According to the official homepage ( https://dev.opera.com/blog/opera-user-agent-strings-opera-15-and-beyond/ ), version 15 and up uses OPR.

So I would regex for both, Opera and OPR