Here is the preference for doing just that: http://www.smalltalkhub.com/#!/~philippeback/HOExtras/packages/Settings-Meta... In fact, I noticed there was no Settings-Metacello and I created one, along with that single pref in it. Maybe will be useful for future things The metacelloPlatformAttributes has been changed like this and put in a *settings-metacello protocol instead of being in "miscellaneous". metacelloPlatformAttributes "Returns the tags for the conditional platform loading in Metacello. Pay attention the order is important: from most to least general." "For release integrators, we should not have #'pharo1.3x' **and** #'pharo1.4.x'" ^ SmalltalkImage Pharo2Compatible ifTrue: [ #(#squeakCommon #pharo #'pharo2.x' #'pharo2.0.x') ] ifFalse: [ #(#squeakCommon #pharo #'pharo3.x' #'pharo3.0.x') ] . Feel free to integrate :-) Phil