Backward compatibility of 10.1 AddIns with 10.0

[DuncanHornby]

All (especially ESRI),

I'm at a cross road with upgrading to 10.1 but some of my clients are locked into 9.x or 10.0. With the release of 10.0 ESRI offered the AddIN, this is great and makes life a lot easier. But I have concerns about compatibility. Can an AddIN built in 10.1 be installed and run in 10.0 assuming it does not use functionality specific to 10.1?  I came across this thread here but no-one seems to have had any success.

So whats the official line on this? 10.1 AddIns are not compatible with 10.0? I hope not!

[JohnHauck · Accepted solution]

Add-ins are not backward compatible. Add-ins targeting 10.1 will not work with 10.0 but would work with a subsequent release like 10.2 for example.

When you compile an ESRI Add-in you are linking to ESRIs Primary Interop Assemblies (PIAs) that are not backwards compatible.

If you need to support clients on 10.x you can compile everything against 10.0 or maintain a 10.0 and 10.1 dev system.