maildirfolder file created in maildir root during auto-creation with 2.3.4.1 but not 2.2.27

5 Feb 2020

      Hello,
as the tin says.
I have several servers running 2.2.27 (Debian stretch) and am adding new
ones with 2.3.4.1 (Debian buster).
The configs were upgraded where needed but neither 10-mail.conf nor
15-mailboxes.conf were changed. 
15-mailboxes is all commented out (I guess the default is auto-create,
which isn't documented anywhere I could find) and the only non-comments in
10-mail.conf are

mail_location = maildir:%h
mail_privileged_group = mail

So yes, no namespaces are explicitly defined/declared.
The 2.3.4.1 version wrongly creates a maildirfolder file in the home
directory (maildir root), preventing exim from correctly creating/using
maildirsize.
a) Is this expected behavior and can it be changed?
b) How can I disable inbox auto-creation if a) doesn't pan out?
Thanks,
Christian
Christian Balzer        Network/Systems Engineer

chibi@gol.com   	Rakuten Mobile Inc.