I just downloaded the latest version mu/mu4e and rebuilt it on my system. That’s a pain because Apple insists on shipping a very old version of Emacs—apparently to avoid GPL 3—and mu4e won’t build because it thinks Emacs is too old. I have to figure out how to get around this every time it comes up. This time I just changed the makefile to point at the proper Emacs in /Applications.
In any event, this is a good time to mention Charl Botha’s post on mu4e 0.9.18. There are a some nice enhancements that Botha describes, which I’ll let you read in his post. One of the nice things about the post is that he provides his mu4e configuration. That’s really handy if you’re just setting mu4e up and want a working, reasonable configuration. He comments it well so you should have no problem adjusting it to your liking.