Available min max values for SMB protocol

I am running Samba 3.6 in SLES 11.4. I recently added in /etc/samba/smb.conf in the [global] section the following - min protocol = SMB2 - max protocol = SMB2 this was done to allow communication with Windows 10 clients that are starting to come online, and also continue to work with existing win7 PCs. **Does anyone know or how can i find out, the available protocols I can use?** I thought, and tried, setting the min & max protocol to SMB2.1 but my test client which is Windows7 immediately fails to connect. I thought SMB2.1 was available in win7? And how do I know SMB2.1 is a valid choice in Samba 3.6? Is SMB3 a valid choice in Samba v3.6?