How do I determine if phone is WAP 1.0 or WAP 1.1

I want to create a page that redirects the user depending on what version of WAP they are using. How do I get collect the relevant information? The PHP get_browser() function doesn't seem to work so I used the $_SERVER['HTTP_USER_AGENT'], which returns the phone model and something called UPLink - is this a browser.

WAP 1.1 phones seem to return UPLink/5.1.2.4 and WAP 1.0 phones seem to return UPLink/4.1.16 - but I want to be sure this is consistant, so can anyone tell me what UPLink is or if there is any other way of checking what WAP a phone is.

Thank you.