TLS Versions Explained: 1.0, 1.1, 1.2 and 1.3
By Nathan Cole, Security Researcher · Updated 2026-06-02Part of our guide to SSL/TLS Certificates Explained: How to Check and Read One.
Support TLS 1.2 and TLS 1.3 today, and disable TLS 1.0 and TLS 1.1, which are deprecated and insecure. That single rule covers almost every real decision about TLS protocol versions. The rest is detail: what changed between releases, why the old ones were retired, and how to confirm what a site negotiates. For background on the certificates these protocols rely on, see SSL/TLS certificates explained.
TLS is the protocol that encrypts a connection after the certificate has been validated. Each version refines the handshake and the set of allowed ciphers. People often blur the terms; if the naming trips you up, SSL vs TLS untangles it, and the same negotiation underpins many of the failures in common SSL errors. A quick history shows why only the newest versions still matter, and the pillar at SSL/TLS certificates explained ties it all together.
A short history
SSL came first, from Netscape in the mid-1990s, and was renamed TLS when the IETF took it over. TLS 1.0 arrived in 1999, 1.1 in 2006, 1.2 in 2008, and 1.3 in 2018. Each step tightened cryptography and closed gaps that attacks had exposed in the version before.
TLS 1.0 and 1.1 are done
Both early versions are formally deprecated. RFC 8996 instructs that TLS 1.0 and 1.1 must not be used, citing weak constructions such as their reliance on MD5 and SHA-1 in the handshake and a lack of modern, authenticated cipher modes. Real attacks, including BEAST and padding oracle issues, made the case concrete. Major browsers removed support years ago, so leaving these versions enabled exposes a server without serving any current client.
TLS 1.2 is the workhorse
RFC 5246 defined TLS 1.2, and it remains widely deployed. It introduced authenticated encryption modes (AEAD ciphers like AES-GCM) and let the handshake negotiate the hash used for signatures, which removed the hardwired MD5/SHA-1 dependency of older versions. Configured with strong cipher suites, TLS 1.2 is secure and stays a sensible fallback for clients that cannot yet speak the newest version.
TLS 1.3 is the current best
RFC 8446 specifies TLS 1.3, the version to prefer. It cuts the handshake to a single round trip in the common case (with an optional zero round trip resumption), which makes connections faster. It also strips out the legacy ciphers that caused trouble, keeping only a small, audited set, and it makes forward secrecy mandatory, so capturing a server's long-term key cannot decrypt past recorded sessions. Fewer options means a smaller attack surface and less room for misconfiguration.
Versions at a glance
| Version | Year | Status | Recommendation |
|---|---|---|---|
| TLS 1.0 | 1999 | Deprecated (RFC 8996) | Disable |
| TLS 1.1 | 2006 | Deprecated (RFC 8996) | Disable |
| TLS 1.2 | 2008 | Current | Support |
| TLS 1.3 | 2018 | Current, preferred | Support and prefer |
What to support today
Enable TLS 1.2 and 1.3, turn off everything older, and prefer 1.3 where the client offers it. That pairing covers every modern browser and API client while keeping deprecated protocols off the wire. Review your cipher list periodically too, since a current protocol version paired with weak ciphers still leaves gaps.
How to check the negotiated version
You can confirm the version a site lands on in several ways. In a browser, open the developer tools security panel and look at the connection details for the page. From a terminal, a command such as openssl s_client -connect example.com:443 -tls1_2 tells you whether a given version is accepted, and the handshake output reports the negotiated protocol and cipher. Automated scanners report the same data across all versions at once, which is quicker when you want the full picture rather than poking at one version at a time.
Curious which TLS versions and ciphers your own site actually offers? Run a free SSL check at DomainIntel and see the negotiated protocol, certificate details, and configuration in one report.
Frequently asked questions
Which TLS versions are still secure?
TLS 1.2 and TLS 1.3 are the current, secure versions. TLS 1.0 and TLS 1.1 are formally deprecated, carry known weaknesses, and should be disabled on any server you control.
What is the difference between TLS 1.2 and 1.3?
TLS 1.3 completes its handshake in fewer round trips, drops legacy and insecure cipher suites, and makes forward secrecy mandatory, so sessions stay safe even if a long-term key is later exposed.
Should I still support TLS 1.0 and 1.1?
No. Both are formally deprecated by the IETF and disabled by default in major browsers, so keeping them enabled adds risk without serving modern clients.