This is a list of symptoms found when using the code and what their cause was. Should some simular symptom appear again it could be useful to take a look at this list. Please fill it with new things discovered.
Cause: the footer edited by Systers was only set with text for dlists. For non dlists it was empty causing a crash with the result of emails not getting send out to subscribers. The problem was solved by a try and except in Mailman/Handlers/Decorate.py, entering the standard Mailman footer for non dlists. For simular cases, check the handlers for possible missing parts.
Cause: the cgidata containing preference for a certain conversation was lost on the way (not always send along) while processing the request. For simular cases (eg. added features not working), use debug statements to check that the neccesary data gets passed along all the way and if they end up missing - find them and add them.
Cause: the cookies trigger certain security issues. Try deleting all your cookies and do the thing again. Using different browsers for the list administrator and the subscribers is also a good idea.
Cause: the update added attributes to the mlist object when creating the list, attributes now missing for old lists. The fix was to make a script to add the missing attributes. For simular cases: as soon as something is added to the mlist object we need to make sure it's there for all lists that might need it. Possibly by writing a script and run it for the lists to add the new attributes.
Cause: the PostgreSQL database was out of sync with the pickle file. To solve it, first run the script find_problems.py located in the bin folder (don't forget to specify the name of the list you want to check). If you get the result that there are subscribers in one DB but not the other, edit the databases manually by either logging in to the psql db or by deleting users in the admin GUI (for more detailed information on how to do this, check the comments for this old bug).