Buster update of qtbase-opensource dfsg-6 to dfsg-7 breaks KMail 4:17.12.3-1

[Andy G Wood <agw@bas.ac.uk>]

The recent update in testing/buster of qtbase-opensource from 5.11.1+dfsg-6 to 
5.11.1+dfsg-7 seems to break KMail 4:17.12.3-1.  The only way I could get 
KMail working again this morning with external imap servers was to downgrade 
to the following:
libqt5concurrent5_5.11.1+dfsg-6_amd64.deb
libqt5core5a_5.11.1+dfsg-6_amd64.deb
libqt5dbus5_5.11.1+dfsg-6_amd64.deb
libqt5gui5_5.11.1+dfsg-6_amd64.deb
libqt5network5_5.11.1+dfsg-6_amd64.deb
libqt5opengl5_5.11.1+dfsg-6_amd64.deb
libqt5printsupport5_5.11.1+dfsg-6_amd64.deb
libqt5sql5_5.11.1+dfsg-6_amd64.deb
libqt5sql5-mysql_5.11.1+dfsg-6_amd64.deb
libqt5sql5-sqlite_5.11.1+dfsg-6_amd64.deb
libqt5test5_5.11.1+dfsg-6_amd64.deb
libqt5widgets5_5.11.1+dfsg-6_amd64.deb
libqt5xml5_5.11.1+dfsg-6_amd64.deb

Andy.