Markus Grandpré writes:
We've encountered an issue with Postorius after migrating from Mailman 2.1. It appears that Postorius is treating email addresses with differing capitalization as distinct user accounts. For example, <markus.grandpre@uni-konstanz.de> and <Markus.Grandpre@uni-konstanz.de> are being recognized as separate identities.
That's not true on the systems I've worked with most recently -- those will be recognized as duplicate addresses, both at list import time and at login on Postorius. Those are versions Mailman 3.3.9 and 3.3.11, with corresponding Postorius. As far as I can tell the last case- sensitivity bugs were fixed as of Mailman 3.2.1 (released 2019-02-22). Postorius does not appear to have had any case sensitivity bugs (not surprising since Postorius just passes them through to Mailman).
I guess it's possible that this is a Debianism, or there was a temporary regression around 3.3.8.
Is there a known configuration option or method within Postorius (or Mailman 3 itself) to normalize or unify account identification, effectively treating email addresses as case-insensitive for account matching?
There is no such configuration option because Mailman has treated email addresses as case insensitive for quite a while. All I can recommend is an upgrade.
Steve