We're often asked the technical question, which version of TLS (or SSL) does Little Green Button use?
TLS v1.2, the most secure cryptographic protocol available.
Caveat - use version 3.7 (or higher) of Little Green Button.
For more detail of how Little Green Button achieves this, read on ....
The More Complex Answer
Little Green Button on the Windows platform adheres to Transport Layer Security (TLS) best practices with the .NET Framework.
Notably, it targets Microsoft.Net Framework v4.7.2, allowing the Windows operating system to negotiate the best available cipher suite. At time of writing, this means TLS v1.2. If a newer protocol becomes available at some point in the future then the operating system can choose to use it without requiring a new version of Little Green Button to be deployed.
Important note - the actual protocol used depends therefore on your client operating system and the host server. Little Green Button servers all include support for TLS v1.2. But we have no control over which protocol is eventually negotiated, that depends on the capabilities of the client.
Here's a network trace showing an example of Little Green Button's external network connections, captured and presented by wireshark.
Observe the highlighted rows - they show the client notifying the server the highest TLS protocol version that it can support.