Dan I was in impression that we should try support all versions of Selenium, as there is not much happening on Selenium end till 2.47.1. But after 2.48+ there has been 7 releases in last 3 months.
Also, with each selenium release, we can't expect it to run on older FF/chrome. So surely it will be nice to keep list of working combinations and inform user to ensure they use 1 of the working combinations.