[quote user="radhx"]My S/MIME plugin is version 1.1.3.4 dt. 2011-01-04, 23:11:32, 916.8KB within the PMSMEn.zip, I hope that is the latest one.[/quote]It's the latest publicly available one, yes.
[quote user="radhx"](when I try to update S/MIME plugin using s/mime-frontend->About->Update option, I get error "Can not read internet data".)[/quote]
I never set up the required web site since the extension isn't really ready for broader public consumption because of all the "hacks" I needed to implement to get it working.
[quote user="radhx"]I have a filtering rule setup to colour all incoming signed mails as
[...]
The colouring rule is not being applied to mails with signature which was being done previously. The only difference being - previously there was only this rule, and now, as I have stopped using Auto-filtering, there are other mails-to-folders filtering rules along with this signature colouring one.
The colouring Expression rule lies somewhere in the middle of all the other Headers mails-to-folder rules.[/quote]
My extension isn't involved in any filterung and colouring at all (there's not need for colouring anyway unless you retrieve email other than via POP3 (IMAP, Mercury or the like)), IOW: There's probably something going wrong with your ruleset only you can figure out.