TLS versions that we can negotiate with the client/server.
| Class Variable | SSLv3 |
Undocumented |
| Class Variable | TLSv1_0 |
Undocumented |
| Class Variable | TLSv1_1 |
Undocumented |
| Class Variable | TLSv1_2 |
Undocumented |
| Class Variable | TLSv1_3 |
Undocumented |