Does the “User Agent” header value ever change?

Question

I am researching methods for detecting mobile devices. Let me preface this by stating that I already know about the WURFL file. One of the other options I am considering is maintaining a list of 'User Agent' header values in-house.

Has anyone seen these header values change for a specific device? I know new ones will pop up as new devices hit the market, but I am more concerned with existing values changing on me.

Answer 1

It is not clear what you are asking but; if a device/phone already on the market no it wouldn't change largely but you should expect change as phone/device gets service updates. goog think about is WURFL that it will try to match the device to a more generic model.

There may be 5 different iPhone 3 S but WURFL would match all as iPhone 3 S

It is hard work to maintain your own user agent list on your own.