I can't find details about what version of TLS is implemented by Secure Gateway. The documentation is very detailed about how to implement TLS, but I can't find the version used. https://www.ng.bluemix.net/docs/services/SecureGateway/index-gentopic3.html#sg_007
Where is this information available?
For the application side TLS, Secure Gateway will accept connections from applications that are using TLS 1, 1.1, 1.2. It is up to the app to decide which version of TLS to connect with. If you want to limit what version of TLS is accepted, you can use the REST API to manage the secure options of your destination. This setting is not configurable via the UI.