=== modified file 'Mailman/Queue/CommandRunner.py'

--- Mailman/Queue/CommandRunner.py	2018-06-17 23:47:34 +0000

+++ Mailman/Queue/CommandRunner.py	2021-03-31 21:53:20 +0000

@@ -100,6 +100,11 @@

             # E.g the outer Content-Type: was text/html

             return

         body = part.get_payload(decode=True)

+        if (part.get_content_charset(None)):

+            body = unicode(body, part.get_content_charset(),

+                           errors='replace').encode(

+                           Utils.GetCharSet(self.msgdata['lang']),

+                           errors='replace')

         # text/plain parts better have string payloads

         assert isinstance(body, StringType) or isinstance(body, UnicodeType)

         lines = body.splitlines()