Mendix uses Dojo 1.3 for its 2.5 releases. For 3.0 Mendix will use Dojo 1.5. Depending on API compatibility and stability Mendix might move to Dojo 1.6/1.7 in later 3.x releases.

As a rule-of-thumb we upgrade those parts of the client that depend on Dojo to the latest stable release of Dojo once we start a new major development/release cycle. This means that the Dojo version shipped with the Mendix tech stack will always lag behind the cutting edge of the Dojo tech.

If you want to use Dojo 1.6 I doubt that it would be for dojo-core. If you want to use code from the dijit or dojox namespace, most of that will run without problems (though you might have deprecation messages) against 1.3.

I think the best option is to check if the specific 1.6 parts you need can be run against the 1.3 core. If you only need a 1.6 widget or some other small standalone item, it's best to check that first.

If you do need the entire 1.6 dojo, you can include that and provide/require them under your widget's namespace. I'm not sure how much the Dojo core supports this though, so you might need to work your way through all the problems that may arise, one by one as you find them.

We sometimes include jQuery with our widgets which works nicely. Have a look at SimpleCharts widget for an example of this.

I think the best option is to check if the specific 1.6 parts you need can be run against the 1.3 core. If you only need a 1.6 widget or some other small standalone item, it's best to check that first.

If you do need the entire 1.6 dojo, you can include that and provide/require them under your widget's namespace. I'm not sure how much the Dojo core supports this though, so you might need to work your way through all the problems that may arise, one by one as you find them.

We sometimes include jQuery with our widgets which works nicely. Have a look at SimpleCharts widget for an example of this.