During the client login process, Open Server negotiates with the client application to agree on a TDS version for all threads. The SRV_S_TDSVERSION property value determines Open Server’s starting point. The client agrees to communicate at or below this starting point. See “Thread properties” for details on the SRV_S_TDSVERSION property. Later on in the login process, the Open Server application can renegotiate the TDS version for a particular thread, using the SRV_T_TDSVERSION property.
Table 2-32 describes the legal values for this property:
SRV_T_TDSVERSION value  | 
Meaning  | 
|---|---|
SRV_TDSNONE  | 
Unknown version of TDS  | 
SRV_TDS_4.0  | 
Negotiation starts at TDS 4.0  | 
SRV_TDS_4_0_2  | 
Negotiation starts at TDS 4.0.2  | 
SRV_TDS_4_2  | 
Negotiation starts at TDS 4.2  | 
SRV_TDS_4_6  | 
Negotiation starts at TDS 4.6  | 
SRV_TDS_4_9_5  | 
Negotiation starts at TDS 4.9.5  | 
SRV_TDS_5_0  | 
Negotiation starts at TDS 5.0  |