Hi Richard,
some thoughts:
- to me this is a Dovecot (upgrade) issue
- it would be helpful to have the whole Dovecot config -> output of
'doveconf -n'
- do you know the new configuration upgrade tool?:
https://dovecot.org/upgrader/
you could try it and see, if there are differences between your current
configuration and the configuration converted by the tool from v2.3
- these outputs of ls for these directories of an example user would also
be helpful:
ls -la /maildirs/username/
ls -la /maildirs/username/.sieve
Best regards,
Markus
