Upgraded from 17.8.x to 18.0.x yesterday - went smoothly. However, now Postfix (3.4.8) receiving mail from the gmail domain started failing to complete delivery with the message:
Feb 19 09:56:46 new postfix/smtpd[28461]: lost connection after BDAT (13266 bytes) from local.server.name[W.X.Y.Z]...
This is happening for me, starting after MU52. The process appears to be hanging during a mysql dump which i see unchanging in ps:
/usr/bin/mysqldump --defaults-extra-file=/tmp/filesGhJTf -h localhost -u admin -P 3306 --quick --quote-names --add-drop-table --default-character-set=utf8...