Issue
A customer is still using Lync Server 2010 and receives the following error when trying to connect to Lync using a Skype for Business 2016 client: “Can’t sign in to Skype for Business: Cannot sign in because the server version is incompatible with Skype for Business. Contact your support team with this information”.
Investigation
Clients running Skype for Business 2015 client can connect successfully. However, the Skype for Business 2015 clients are only able to connect because of the presence of the following registry key (for Office 2015) on their machines:
Key: HKLM\SOFTWARE\Policies\Microsoft\Office\15.0\Lync
Name: DisableServerCheck
Type: DWORD
Value: 1 (00000001)
Resolution
Add the following registry key for Office 2016. Reboot the client and they will be able to connect to Lync.
Key: HKLM\SOFTWARE\Policies\Microsoft\Office\16.0\Lync
Name: DisableServerCheck
Type: DWORD
Value: 1 (00000001)
Note you could also use Group Policy Settings for Skype for Business to deploy this setting.
Group Policy Setting: Disable server version check (DisableServerCheck)
Description: If you set this policy to 1, prevents Skype for Business from checking the server name and version before signing in. By default, Skype for Business makes these checks before signing in.
