Can VSPackage extensions build by VS2015 be compatible with VS2012?

I plan to develop a VSPackage extension intended to be applicable both to VS2012 and VS2015. The question is, assuming the actual content of the package is compatible/applicable to both versions, if the package is implemented/built using VS 2015 SDK, will it be compatible/applicable to VS2012 also. Prior experience with packages development (Lightswitch) is that you define the package compatibility settings but not suse 2012 is an option for a package build using VS2015.

Thanks

Kostas

1+1 = 3 for large values of 1