Howdy, I recently updated from mailman 2.1.? to 2.1.26.  After this update users can not subscribe or unsubscribe.  Here is the error from the mailman log.  Any ideas what I need to fix?  It may be a database problem? Thanks Jeff Mar 27 08:57:49 2018 admin(21493): @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@  admin(21493): [----- Mailman Version: 2.1.26 -----]  admin(21493): [----- Traceback ------]  admin(21493): Traceback (most recent call last): admin(21493):   File "/var/lib/mailman/scripts/driver", line 117, in run_main admin(21493):     main() admin(21493):   File "/var/lib/mailman/Mailman/Cgi/subscribe.py", line 113, in main admin(21493):     process_form(mlist, doc, cgidata, language) admin(21493):   File "/var/lib/mailman/Mailman/Cgi/subscribe.py", line 248, in process_form admin(21493):     mlist.AddMember(userdesc, remote) admin(21493):   File "/var/lib/mailman/Mailman/MailList.py", line 923, in AddMember admin(21493):     cookie = self.pend_new(Pending.SUBSCRIPTION, userdesc) admin(21493):   File "/var/lib/mailman/Mailman/Pending.py", line 85, in pend_new admin(21493):     evictions = db.setdefault('evictions', {}) admin(21493): AttributeError: Message instance has no attribute 'setdefault' admin(21493): [----- Python Information -----]  admin(21493): sys.version     =   2.7.12 (default, Dec  4 2017, 14:50:18)  [GCC 5.4.0 20160609]  admin(21493): sys.executable  =   /usr/bin/python  admin(21493): sys.prefix      =   /usr  admin(21493): sys.exec_prefix =   /usr  admin(21493): sys.path        =   ['/var/lib/mailman/pythonlib', '/var/lib/mailman', '/usr/lib/mailman/scripts', '/var/lib/mailman', '/usr/lib/python2.7/', '/usr/lib/python2.7/plat-x86_64-linux-gnu', '/usr/lib/python2.7/lib-tk', '/usr/lib/python2.7/lib-old', '/usr/lib/python2.7/lib-dynload', '/usr/lib/python2.7/site-packages', '/usr/lib/python2.7/dist-packages']  admin(21493): sys.platform    =   linux2  admin(21493): [----- Environment Variables -----]  admin(21493): CONTENT_LENGTH: 97  admin(21493): CONTENT_TYPE: application/x-www-form-urlencoded  admin(21493): HTTP_COOKIE: mml+admin=280200000069254aba5a732800000030306232313361323236663763306465363935393631613539633061313537633030623963303764; ajs_anonymous_id=%22d8f8ca92-1109-40e3-9415-0fd09ac14d87%22; _ga=GA1.2.4794311.1490733873; ajs_user_id=null; __utmz=194481448.1521488781.5.2.utmcsr=google|utmccn=(organic)|utmcmd=organic|utmctr=(not%20provided); ajs_group_id=%223ff0c525-2764-40c1-9653-b402a1c34211%22; _hp2_id.4205778290=%7B%22userId%22%3A%222302352706526137%22%2C%22pageviewId%22%3A%225888385097105288%22%2C%22sessionId%22%3A%228880360585997038%22%2C%22identity%22%3Anull%2C%22trackerVersion%22%3A%223.0%22%7D; __utmc=194481448; _gid=GA1.2.1014496654.1522088903; __utma=194481448.4794311.1490733873.1522089078.1522096859.8  admin(21493): SERVER_NAME: mopar.tamu.edu  admin(21493): SERVER_PROTOCOL: HTTP/1.1  admin(21493): PYTHONPATH: /var/lib/mailman  admin(21493): REMOTE_ADDR: 128.194.139.52  admin(21493): REQUEST_SCHEME: http  admin(21493): SCRIPT_NAME: /mailman/subscribe  admin(21493): REQUEST_METHOD: POST  admin(21493): HTTP_HOST: mopar.tamu.edu  admin(21493): PATH_INFO: /mml  admin(21493): SERVER_PORT: 80  admin(21493): REMOTE_PORT: 57518  admin(21493): QUERY_STRING:   admin(21493): REQUEST_URI: /mailman/subscribe/mml  admin(21493): DOCUMENT_ROOT: /var/www/html