We do support IE8(and IE7) in all versions of CanJS. Note, if you plan
on using can.Component in IE8, you'll need Google's HTML5Shiv to make
things play nice.
Developer
Bitovi
JMVC 3.3 can be used with CanJS 2.1.2.
JMVC 3.2.4 is not directly supported anymore as we've broken the
projects up individually, however there are plans for a new JMVC in
the future.
That all being said, if this is a greenfield project I'd recommend
using the latest CanJS with the latest Steal(or loader of choice).
Both have up to date documentation and guides(canjs.com and
stealjs.com respectively).
Developer
Bitovi