I am wondering if it is a good idea to use rem in my mobile website. Doing so makes life a lot easier but I don't have any older devices to test on and I can't find any clear information on support in ie mobile.
CSS3 has the new “rem” unit which picks up the root (html) fontsize....IE7 and 8 don't support it but does it matter? no, since you mention Mobile and therefore rem should be fine. but you want to check for testing different mobile os/versions? Try this:
From the looks of it really old mobile OS and old ie dont support it