TLS 1.2 and 1.3 only: Crawl Audit check 143

Short answer: TLS is the protocol behind HTTPS. Versions 1.0 and 1.1 are formally retired, so your server should accept only TLS 1.2 and 1.3. Check 143 reads which version your server agreed to and, in the full audit, also tries to connect with an old version.

What Crawl Audit checks

• Fail (full audit): the server accepts a TLS 1.0 or 1.1 connection.
• Pass: the connection used TLS 1.2 or 1.3.
• Warning: the connection used an older version.
• If the version can't be read, an HTTPS site passes.

The free check only sees the version your server chose, which is normally the newest it supports. A server that still allows TLS 1.0 for old clients can pass the free check and fail the full one.

What the sources say

• RFC 8996 (2021): "This document formally deprecates Transport Layer Security (TLS) versions 1.0 (RFC 2246) and 1.1 (RFC 4346)."
• UK NCSC: "You should use TLS 1.3 and/or TLS 1.2, configured with the Recommended Profiles." And: "You should disable TLS 1.1 and 1.0."
• The NCSC adds that sites on TLS 1.2 only will need a plan to move to TLS 1.3 for post-quantum cryptography in future.

Turning old versions off

• On a managed host or CDN, look for a minimum TLS version setting and set it to 1.2.
• On your own server, Mozilla's SSL Configuration Generator gives a ready-made config. Its "intermediate" profile allows TLS 1.2 and 1.3.
• Very old devices that only speak TLS 1.0 will stop connecting, so check your analytics if you serve an unusual audience.

On devmarde.com

Our site connected with TLS 1.2 and TLS 1.3 on 6 October. We host on Vercel, whose docs list TLS 1.2 and 1.3 as the supported versions. Our own test machine couldn't attempt a TLS 1.0 connection, so for that part we're relying on Vercel's docs.

Sources

• IETF, RFC 8996: Deprecating TLS 1.0 and TLS 1.1 (March 2021).
• NCSC, Using TLS to protect data (reviewed 10 December 2025).
• Mozilla, SSL Configuration Generator, and Vercel, Encryption (updated 15 September 2026), checked 6 October 2026.