看到 AWS 的公告，宣佈 CloudFront 支援 TLS 1.3：「Amazon CloudFront announces support for TLSv1.3 for viewer connections」。
預設會自動啟用：
TLSv1.3 is available today and enabled by default across all Amazon CloudFront security policies options. No additional changes are required to your CloudFront configuration to benefit from the security and performance improvements of TLSv1.3 for your viewer connections.
對使用者最大的差異應該還是改善 first byte 的時間 (主要是因為 handshake 時間縮短)，這點 AWS 的人也有提到在內部測試時，美國區的改善情況：
In our own internal tests in the US region as an example, first byte latency for new negotiated connections saw reductions of up to 33% for TLSv1.3 compared to previous versions of TLS.
在 latency 更高的地區應該也會有大幅改善...