Is version 3.0 of ADFS supported for SSO with Transact?
I stand corrected. The Answer is it is currently supported, tested platform and has been implemented at several clients.
I believed our test server was ADFS 2.1 which comes on Windows Server 2012, I followed up with Anton has confirmed that our latest test server is ADFS 3.0 on Windows Server 2012r2. ADFS3.0 is also on Windows Server 2016.