Microsoft has posted a blog post detailing what effect the roll-out of new Mango apps, which have features which are not compatible with Windows phone 7 NoDo, will have on Marketplace.
It appears once a developer updates an app for Mango, the NoDo version of their app will be held in frozen, available for users who are still on NoDo, but with the developer no longer being able to provide updates for that version of the app.
Only one entry will exist in Marketplace, which will need to be shared by both the NoDo and Mango version. Microsoft expects developers to provide detailed descriptions and screen shots specifying which features are Mango only. Even screen shots will have to be shared, with developers needing to label Mango vs NoDo shots.
Hopefully the Mango roll-out will proceed rapidly and smoothly, else we anticipate this procedure causing tremendous issues for developers wishing to support both their NoDo and Mango customers for the possible 2-3 months it may take to roll out Mango in the worst case scenario.
Read more at the Windows team blog here.