What are the considerations when trying to build an AppExchange Application that works for Group or Professional Edition? I understand that there are a lot of Professional edition org and it would be great to be able to have them as customers too.
Building for 'Group Edition' and 'Professional Edition' there are some things to keep in mind:
You should always attempt to install your app into a PE and GE edition org before releasing it to the AppExchange in order to confirm it's interoperability so that users coming in from the AppExchange don't encounter issues.
I'm giving a presentation at Dreamforce '12 that Includes notes on supporting and testing multiple editions. It's called
It is very important to note that when a feature is listed as "Not Supported" in GE/PE, this means there can be NO API references to the feature throughout your Code. For instance, here are some gotchas related to non-supported features in GE/PE:
Furthermore, you might think that deprecating a method or part of your code that uses a not-allowed API object would allow successive versions to be allowed in GE/PE. Nope!
Also, a couple of features not supported in either GE or PE orgs not mentioned in Jordan's answer: