Lync applications/utilities built using either the 2010 or 2013 client-side API software development kit (SDK) are supposed to work against all 3 major releases of the Lync client: 2010, 2013 & 2013 Basic. This means if you upgrade your client from Lync 2010 to the 2013 release, your third party utils (like my Profiles for Lync, Elyza and HIDnLync) should all still work.
The wheels will however fall off if you have *both* the 2010 and 2013 clients installed on your PC. If you use a 2010 util against the 2013 Client (or vice versa), the util will be unable to establish a connection with the client and will throw an error. (In newer builds of my utils, you’ll be linked to this page).
In this situation, you need to use a build of the util compiled with the same SDK version as the client. For this reason and for the time being I’ll continue to release two versions of each util, although end users with only one version of the client installed need only install either version of the utility.
Both builds of Elyza and HIDnLync operate exactly the same. For Profiles for Lync, I recommend you use the 2013 version, as the 2013 SDK fixed a bug in its predecessor that manifests itself when you’re switching between sites with Manual or Automatic host discovery.