Philip Guenther found the key to Alex Schroeder's problem:
| I finally checked the procmail HISTORY file, and sure enough, grepping
| for "case" gives:
| 1994/08/30: v3.06
| ...
| Changes to procmail:
| - Fixed a bug which was present since v2.30: 'z' was always
| handled case sensitive (seems like not many people use
| that letter :-) in regular expression conditions
Very good sleuthing, Philip!
For anyone who wants filled in what Philip left implicit, Alex's choices are
to upgrade to a more recent version of procmail or to change the condition to
this:
* ^Subject:.*atlantis.*[Zz]eitung