I have a CCM 6.12a system and had upgraded from earlier version awhile ago. I had set up dial rules on 6.12a and they worked for my Attendant Console for modifying the number when dialed. We recently rolled out some new users on AC and downloaded AC from CCM and the dial rules did not work for new users. Turned out the users who worked somehow didn't get their AC version updated to version that came with 6.12. So were still a 5.x version of AC and working fine.
Anyway, I also tried the AC version from 7.1.2a SU1 on this system and same problem as 6.12a AC version but when I install AC version from CUCM 6.01 everything works fine.
The dial rule is set up for example, to match number starting with 1815 and 11 digits long and keep last 4 digits.
The users in AD have telephone numbers like +1 815 555 1234. In the working AC versions it converts the telephone number from AD into the last 4 digits.
On the AC versions (6.1.1 and higher it seems) where the dial rules stop working it doesn't modify the number at all and when you click on it it tries to dial the number with the + sign included. I also tried to add a dial rule for "+1 815" and "+1815" but that had no success. The AcClient log shows all the dial rules being downloaded fine. I also tried to set these rules on the PC itself with the DialRules.xml file with out luck.
I am aware that Call Manager 7.x added support for + dialing so maybe they changed something in newer AC versions for that?