Hello,
Actually C:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\IDE\Extensions\DEVSENSE\PHP Tools\Devsense.PHP.Composer.dll is just our assembly that enables us to work with Composer.
Actual Composer is located here C:\Users\Miloslav\AppData\Local\DEVSENSE\Composer\composer.phar
Anyway we do update the composer periodically. In your case, it just happened that there is a new version and we didn't update it yet.
If you'd like to force update, delete this file C:\Users\Miloslav\AppData\Local\DEVSENSE\Composer\composer.phar and next composer command will download the latest Composer version.
Please let me know if that helped.
Thanks!