Basically I have ArcMap 10.1 and SDK for ,NET 10.1 and Java 10.1 installed. I have built an application using this SDK for some operations on the feature classes. Now I found out that the end users mostly have 10.0 version of Arcmap and no SDKs installed. So the question is do I need a separate license for each version of Arcmap (10.0, 10.1, 10.2) to build an application that targets 10.0, 10.1 and 10.2 runtime environments? I think the functionality used is simple and probably is included in 10.0 APIs. The other question is whether it's possible to distribute only one application (e.g. built for 10.0) for all newer versions of the Arcmap or I need a three separate distribution packages for every version of the Arcmap. Finally, can I access 10.0 SDK having the license for 10.1 SDK?