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+Maildir++ quota
+===============
+
+Maildir++ is the most commonly used quota backend with Maildir format. Note
+that *Maildir++ quota works only with Maildir format*. With other mailbox
+formats you should use <count quota> [Quota.Count.txt]. Dovecot implements the
+standard Maildir++ specification
+[http://www.courier-mta.org/imap/README.maildirquota.html], so it's compatible
+with Courier [http://www.courier-mta.org/], maildrop
+[http://www.courier-mta.org/maildrop/], Exim [http://www.exim.org], etc.
+
+There are two ways to configure Maildir++ quota limits:
+
+ 1. Configure the limits in Dovecot. You most likely want to do this. See
+    <quota main page> [Quota.txt] for how to do this configuration.
+ 2. Make Dovecot get the limits from existing 'maildirsize' files.
+
+Only Maildir++-specific settings are described below. See <Quota.txt> for more
+generic configuration.
+
+Maildir++ quota relies on 'maildirsize' file having correct information, so if
+your users can modify the file in some way (e.g. shell access), you're relying
+on the goodwill of your users for the quota to work.
+
+You can't rely on Dovecot noticing external changes to Maildir and updating
+maildirsize accordingly. This happens eventually when quota is being
+recalculated, but it may take a while. Quota recalculation also currently
+doesn't trigger quota warning executions.
+
+Maildirsize file
+----------------
+
+The 'maildirsize' file in the Maildir root directory contains both the quota
+limit information and the current quota status. It contains a header in format:
+
+---%<-------------------------------------------------------------------------
+<storage limit in bytes>S,<messages limit>C
+---%<-------------------------------------------------------------------------
+
+If you don't configure any quota limits in Dovecot ('quota=maildir' with no
+other settings), Dovecot takes the limits from the header. If the file does not
+exist, quota isn't enforced.
+
+If you configure quota limits in Dovecot, Dovecot makes sure that this header
+is kept up to date. If the file does not exist, it's simply rebuilt.
+
+Once the 'maildirsize' reaches 5120 bytes, the quota is recalculated and the
+file is recreated. This makes sure that if quota happens to be broken (e.g.
+externally deleted files) it won't stay that way forever.
+
+(This file was created from the wiki on 2019-06-19 12:42)