[Dovecot] Dovecot IMAP is broken after upgrade from 2.1.2 to 2.1.3

[Michael Neubert]

The problem starts just after authorization:

Console:

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openssl s_client -connect mailserver.com:993
* OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE 
IDLE AUTH=PLAIN] Dovecot ready.
a login "username" "password"
closed
###################################################################

Here are the logs of this moment:

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Mar 24 13:48:46 imap-login: Info: Login: user=<username>, method=PLAIN, 
rip=xxx.xxx.xxx.xxx, lip=yyy.yyy.yyy.yyy, mpid=10662, TLS
Mar 24 13:48:46 imap-login: Warning: SSL alert: where=0x4008, ret=256: 
warning close notify [xxx.xxx.xxx.xxx]
Mar 24 13:48:46 imap(username): Info: Connection closed in=0 out=303
###################################################################

So just after sucussful login with correct username / password the 
connection is closed.