Since PhoenixMiner is up to 5.5c at this point, for the vast majority of people, there is no need to stick with the old AMD drivers as long as you aren't locked into an old version of PhoenixMiner(for whatever reason).   Note that AMD drivers 21.3.1 and 21.3.2 have significant problems for mining at the moment, and many of us are waiting for the next version of PhoenixMiner, 5.6, or 5.5d, or whatever the next version gets called.   Radeon Settings 21.1.1 worked very well, 21.2 series has a few issues from my experience, though 21.2.3 works decently(21.2.1 was problematic and 21.2.2 was better, but still had problems).