On September 15, 2026, GitHub turned off SHA-1 for HTTPS and TLS on github.com and its CDNs. They had been warning about it since April. If your client can't do a TLS handshake without SHA-1, you now get a connection error. I'll skip the history lesson on SHA-1. What I want to cover is why this took until 2026 to finally happen, and how to check your own setup first. Why was SHA-1 still around TLS handshake is the part where your client and github.com agree on how to verify th...