This file contains some important notes on upgrade process.

 * Upgrading from 1.5.x to 1.6.x:
	1. Upgrade and restart mfsmaster.
	2. Upgrade and restart chunkservers.
	3. Upgrade mfs clients (mfstools before remounting MooseFS with new mfsmount),
	   remount MooseFS trees.

	mfstools 1.6.x work with MooseFS 1.5.x, but not the opposite: old mfstools
	no longer work with MooseFS 1.6.x.

	mfsmount 1.5.x will work with mfsmaster 1.6.x only if REJECT_OLD_CLIENTS
	option in mfsmaster.cfg isn't set to 1. mfsexports.cfg file won't be used
	when authorizing 1.5.x clients.

 * Upgrading from 1.6.19 to 1.6.20

	Upgrade and restart mfsmaster before upgrading any chunkserver.