A documentation slip may cause users to lose mail
gateway customisations.

Having recently upgraded from roundup version 0.7 to
1.1 I followed the upgrade path as recommended at
http://roundup.sourceforge.net/doc-1.0/upgrading.html.
In the section at
http://roundup.sourceforge.net/doc-1.0/upgrading.html#new-tracker-layout
it says "the old interfaces.py file will be ignored"

Hence we moved interfaces.py into the new extensions
directory, and our customisations for web interface
transferred smoothly.

Unfortunately "interfaces.py" is not ignored by the
mail gateway, and so we lost those customisations.

Having discovered the problem a restored (a shorthened
version of) interfaces.py to the root directory of the
tracker our mail customisations are restored.