Thanks for your confirmation shamim! I tested around and found out that downgrading to exim 8.42 works while 4.84 is failing. (running pcre 8.34) Removing remove_header solves the problem (but kills features of course) while add_header doesnt seem to be making similar problems (no help in that case of course – I was just curious). While I was lazy by using exim4u it looks like the time has come to make my own hands dirty and ready through all configs and start fully understanding them :) Von: users [mailto:users-bounces(a)exim4u.org] Im Auftrag von Shamim Shahriar Gesendet: Donnerstag, 04. September 2014 01:39 An: Exim4U General Discussion Betreff: Re: [Exim4U] exim 4.84 On 03/09/2014 11:27, Odhiambo Washington wrote: There are two servers on which I am running 4.84 with Exim4U and I don't seem to have a problem. However, I noticed during upgrade that the 4.84 also wanted an updated version of PCRE so you may need to take care of that if you didn't already. On 3 September 2014 13:10, Gordon Dickens <gecko(a)exim4u.org <mailto:gecko(a)exim4u.org> > wrote: That is interesting but should not be happening. I have not tested exim 4.84 yet but it should be backwards compatible with earlier versions... You may want to make a post to the exim-users(a)exim.org <mailto:exim-users(a)exim.org> list to inquire if they have changed something that might cause this behavior. You can subscribe to the exim-users list here: http://www.exim.org/mailman/listinfo/exim-users FYI, Gordon Hello I can confirm that this is more likely a compatibility issue. Here is what I have found so far. But I might be thoroughly mistaken (not being very experienced in such things always leaves that possibility) All routers that have header_remove and the select statement inside fails to expand, resulting in something like below 16:14:55 19977 failed to expand: select users.sa_tag * 10 from users,domains where local 16:14:55 19977 error message: missing } at end of string If you comment out the header_remove, or keep it very very simple, then it works. Reading this thread I checked my PCRE (which was latest by the way), tried different version, didn't make any difference. Also, I have other systems running older version of exim, but fairly recent (and on one particular the latest) version of PCRE, they are working without any issue. The only problem I found was the one with the latest exim. I'm *almost* certain I'm missing something, but cannot put my finger on it. Just my 2p Thank you SS