== My change to a source module is inneffective; When do I need to restart Mailman? ==

{{{#!wiki note
This is specific in detail to Mailman 2.1, but similar considerations apply to Mailman 3.
}}}

Mailman's qrunners are persistent processes and will not
reload any previously loaded modules unless Mailman is restarted.

In general, if you change any .py file in Mailman/ or subordinates
except Mailman/Cgi/, you must restart Mailman for the change to be
effective. Mailman/Cgi/ is an exception because what's there is only
used by web CGI processes which are not persistent.

It's also necessary to restart Mailman if you change any templates/
files having to do with the pipermail archive because !ArchRunner keeps a
cache of templates.

Also, regenerating .py[co] files is not necessary. Upon import
of a module, python will see the .py is newer and load and compile it
and if it has permission, write the .py[co] file it will use the next time.