For Squid 2.7 - IntelligentMirror 1.0.1-1
For all others - IntelligentMirror 0.5-1

Note : IntelligentMirror 0.5-1 works well with all the versions of
squid but IntelligentMirror 1.0.1-1 is almost 250% more efficient
than 0.5-1. So you must choose 1.0.1-1 if you have squid 2.7.