Index: mailman-3.3.6/setup.py
===================================================================
--- mailman-3.3.6.orig/setup.py	2022-10-27 11:14:04.065047157 +0200
+++ mailman-3.3.6/setup.py	2022-10-27 11:15:25.901631179 +0200
@@ -113,7 +113,7 @@ case second 'm'.  Any other spelling is
         'aiosmtpd>=1.4.1',
         'alembic>=1.6.2,<1.9.0',
         'atpublic',
-        'attrs<21.3.0',
+        'attrs<22.2',
         'authheaders>=0.14.0',
         'authres>=1.0.1',
         'click>=8.0.0',
Index: mailman-3.3.6/src/mailman.egg-info/requires.txt
===================================================================
--- mailman-3.3.6.orig/src/mailman.egg-info/requires.txt	2022-10-27 11:02:22.972052996 +0200
+++ mailman-3.3.6/src/mailman.egg-info/requires.txt	2022-10-27 11:15:33.805687581 +0200
@@ -1,7 +1,7 @@
 aiosmtpd>=1.4.1
 alembic<1.9.0,>=1.6.2
 atpublic
-attrs<21.3.0
+attrs<22.2.0
 authheaders>=0.14.0
 authres>=1.0.1
 click>=8.0.0