If I create a filtering rule with a "Message Subject Contains" criteria, it will match against messages with a plain-text subject line, but not if the subject uses UTF-8, or other such encoding.
For example, if I create a rule -> Message Subject Contains: testing
it will match this:
Subject: I am testing
but not this:
Subject: =?UTF-8?Q?I_am_testing?=
even though they are semantically equivalent.
Mailbox Filtering & UTF-8 Encoding
Re: Mailbox Filtering & UTF-8 Encoding
Any updates here? I'm experiencing the same issue. A lot of spam makes it through because of it.