Mailing list changes.

I noticed starting today the Sender: header is no longer included on the mailing list. I used to use the Sender: header in sieve rules for sorting. Now the list emails only come From: rando email addresses. On the postfix mailing list it replaces the From: header with the list address instead of keeping the original email author.

Is this the future intended behavior? Or can we get a Sender: or From: header to contain the list address for sorting?