Is there any point in writing pre-Mango (7.0) Windows Phone 7 applications

Question

Inspired by an exchange on a recent question, I wanted to know whether there is any good reason to develop Windows Phone 7 applications that target pre-Mango models, i.e. by

Answer 1

There isn't much of a reason to target pre-Mango as opposed to Mango as the upgrade is available to all models of phone currently, and for free.

It is worth keeping on the latest SDK for no other reason than there is no reason not to... lol, made sense in my head. Things like performance improvements, bug fixes, new features etc are all reasons to keep up with the latest, as you are likely aware.

The only reason I would target an older SDK is if a particular version of the phone OS was not available to a certain piece of hardware for any reason.

Then again, if you can make your app with the lowest common SDK, why not - it will in theory only increase your user base as backwards compatibility is enforced, over choosing a newer and not-completely-rolled-out version. You just personally suffer the older APIs and miss out on new features. However, I see this counter-point as a largely academic argument and adds little weight to the choice of older versions.

Save yourself the headache, go with the new stuff. Anyone actively using their phone enough to also use your app is likely hot on updates.