I took over a Windows Phone project which was previously targeting WP 7.1 platform, and with the recent announcement of the new platform it should target WP 8 as well.

My VS 2010 solution consists on several projects (Data access, Model, Tests and WP7 client app) and i am wandering on how to include support for WP8.

I have to note that the code-base is not compatible with WP8, due to usage of Toolkit controls and other 3rd party libraries targeted for WP7.1 specifically.

Also there is another problem with the Visual Studio versions - WP7.1 can work with VS 2010, but WP8 requires VS 2012. Should i move the whole code-base to VS 2012?

Any good advice on how to organize code-base in a most meaningful way in order to avoid duplication and possible painful maintenance?

I am thinking between one solution - multiple projects vs. multiple solutions - reusable projects approach. Code duplication (like two separate folders/solutions) should be the least possible approach (fallback).