A solution is to specify the key exchange algorithm on the command line:
More information can be found on OpenSSH's Legacy Options page.
I spent a bit of time baffled after installing Atmel Studio 7.0.634 as I couldn't even create a new project successfully. This appears to be an incompatibility with Visual Studio 2015 Update 1. I found an apparent solution to the issue here, which manages to get me past my issues with creating a project. I'm not exactly sure why Atmel Studio has so many binding redirects, but there it is.
Sample error message: The 'ErrorListPackage' package did not load correctly.