I'm going to raise this in our next meeting (Tuesday) and see if there's a way we can have IMAP flags exposed somehow. Along with fast cross-folder searching o

I'm going to raise this in our next meeting (Tuesday) and see if there's a way we can have IMAP flags exposed somehow. Along with fast cross-folder searching on flags, we could quite easily implement virtual folders per flag - which I think fills your use-case perfectly. The difficult parts are: 1) UI 2) limits. We have a hard limit of 128 "user flags" because it's in 4 x 32 bit fields in a fixed-width data format. Subtract a few for our internal tooling, and you probably only have 120 you can use for yourself. Would 120 be enough? One thing that many older clients did was had $Label1 => $Label5. That was often enough for people... so I suspect 120 is probably fine.