Blue Wallet promised they would start to support below 1 sat/vByte transactions mid-July. I can see in the release notes that this PR has been included in the 7.2.0 release. They have also fixed a fee display bug that showed the fees in an untraditional format. I guess the version is being rolled out in stages because I still haven't received the update for my Android phone. I am not in a hurry. It will be there.