RE: Problem email client iPhone ios18.2

Well, I uncommented the imap_capabilities flag and REMOVED the IDLE capability and now iOS 18 Mail client is getting and syncing emails. I suspect the folks over at Stalwart were on to something .... I just don't know why command pipelining had to be added by Apple for the important IDLE feature.

I don't really understand what you mean, is idle enabled by default? My config has

imap_capability = +SPECIAL-USE