This is a guest post from Apple’s Secure Transports team about TLS protocol version deprecations. This announcement may require changes for your websites.

Transport Layer Security (TLS) is a critical security protocol used to protect web traffic. It provides confidentiality and integrity of data in transit between clients and servers exchanging (often sensitive) information. To best safeguard this data, it is important to use modern and more secure versions of this protocol. Specifically, applications should move away from TLS 1.0 and 1.1. Doing so provides many benefits, including:

Modern cryptographic cipher suites and algorithms with desirable performance and security properties, e.g., perfect forward secrecy and authenticated encryption, that are not vulnerable to attacks such as BEAST.

Removal of mandatory and insecure SHA-1 and MD5 hash functions as part of peer authentication.

Resistance to downgrade-related attacks such as LogJam and FREAK.

Now is the time to make this transition. Properly configured for App Transport Security (ATS) compliance, TLS 1.2 offers security fit for the modern web. It is the standard on Apple platforms and represents 99.6% of TLS connections made from Safari. TLS 1.0 and 1.1 — which date back to 1999 — account for less than 0.36% of all connections. With the recent finalization of TLS 1.3 by the IETF in August 2018, the proportion of legacy TLS connections will likely drop even further. TLS 1.2 is also required for HTTP/2, which delivers significant performance improvements for the web.

Therefore, we are deprecating support for TLS 1.0 and 1.1. Complete support will be removed from Safari in updates to Apple iOS and macOS beginning in March 2020. Firefox, Chrome, and Edge are also planning to drop TLS 1.0 and 1.1 support at that time. If you own or operate a web server that does not support TLS 1.2 or newer, please upgrade now. If you use legacy services or devices that cannot be upgraded, please let us know by contacting our Web Technologies Evangelist or by filing a bug report with details.