Well actually, seeing as my filters only exclude what they understand (and figure out to be uninteresting) and let through everything else - any change in the header would result in them breaking and having to be fixed-up.
can you tell me the real filter? since i do not realy belive it should have to change:-)
~/.procmailrc
It could still use a lot of work, but it mostly works...
...
################################## ##### REMOVE DUPLICATE MAILS ##### ##################################
:0 Whc: mail/.msgid.lock | formail -D 65536 mail/.msgid.cache
:0 a: /dev/null
############################### ##### CENTOS-ANNOUNCE BEG ##### ###############################
##### Ignore Digests :0 H * ^Subject: [CentOS] CentOS-announce Digest, Vol [0-9]+, Issue [0-9]+$ /dev/null
##### Accept valid errata for CENTOS 4 i386 :0 H * ^Subject: [CentOS-announce] CE[SBE]A-200[5-9][-:]([0-9][0-9][0-9](-[0-9][0-9])?|xxx|[01][0-9][0-3][0-9]-[0-9][0-9][0-9]):? ((Critical|Important|Moderate|Low|Information|BUG fix|Bugfix|Enhancement|None) |)CentOS 4(.[0-9])? i386 /var/spool/mail/maze
##### Ignore any other valid errata :0 H * ^Subject: [CentOS-announce] CE[SBE]A-200[5-9][-:]([0-9][0-9][0-9](-[0-9][0-9])?|xxx|[01][0-9][0-3][0-9]-[0-9][0-9][0-9]):? ((Critical|Important|Moderate|Low|Information|BUG fix|Bugfix|Enhancement|None) |)CentOS [234](.[0-9])? (i386|ia64|x86_64|s390|s390x|s390(x)|ppc|ppc32|ppc64|axp) /dev/null
##### Accept other CENTOS 4 :0 H * ^Subject: [CentOS-announce] .*CentOS( |-|)4 /var/spool/mail/maze
##### Ignore other CENTOS 2/3/4 :0 H * ^Subject: [CentOS-announce] .*CentOS( |-|)[234] /dev/null
##### We should possibly do something about Product Releases #* ^Subject: [CentOS-announce] Release Announcement: $name $version $arch
##### Accept anything else which hasn't been classified... :0 H * ^Subject: [CentOS-announce] /var/spool/mail/maze
############################### ##### CENTOS-ANNOUNCE END ##### ###############################
:0 /var/spool/mail/maze