This documentation is for Dovecot v2.x, see wiki1 for v1.x documentation.

The UIDPLUS extension of the Internet Message Access Protocol (IMAP) provides a set of features intended to reduce the amount of time and resources used by some client operations. The features in UIDPLUS are primarily intended for disconnected-use clients.

You can read more about UIDPLUS at

Note that this RFC is dated December 2005 so may include some very recent proposals not in the original UIDPLUS RFC.