If you upgrade to Windows 10, then I am afraid the software will not work. This is the official answers since it's specified on the website that Topcon Link is working only on the following versions of Windows: Microsoft Windows XP, Windows Vista, Windows 7 (32 and 64 bit).
Unofficially, the software might run on Windows 10 with the help of Compatibility. The problem is that you can't download the software to test it, but if you already have it. Upgrade to Windows 10 and then you can go back to Windows 7. You have this possibility for 1 month since the upgrade is initiated.