Deprecation of TLS 1.1 for Email Submission and Access
updates
- rfc-8314 — Cleartext Considered Obsolete: Use of Transport Layer Security (TLS) for Email Submission and Access
Extracted elements (8)
RFC 8314 previously set the minimum recommended TLS version at 1.1. Because TLS 1.1 has been deprecated by RFC 8996, the minimum is raised to TLS 1.2 to align email submission and access guidance with the broader TLS deprecation.
Servers refusing connections based on TLS version should refuse any ClientHello.version field corresponding to any version of SSL or TLS earlier than TLS 1.2, replacing the prior threshold of TLS 1.0.
As soon as practicable, MSPs currently supporting SSL 2.x, SSL 3.0, TLS 1.0, or TLS 1.1 SHOULD transition their users to TLS 1.2 or later and discontinue support for those earlier versions of SSL and TLS.
If an MUA provides a confidentiality indication, it MUST NOT indicate confidentiality for any connection that does not at least use TLS 1.2 with certificate verification and meet the minimum confidentiality requirements associated with that account.
It is RECOMMENDED that new users be required to use TLS version 1.2 or greater from the start. However, an MSP may find it necessary to make exceptions to accommodate some legacy systems that support only earlier versions of TLS or only cleartext.
MUAs MUST implement TLS 1.2 or later (e.g., TLS 1.3). Earlier TLS and SSL versions MAY also be supported, so long as the MUA requires at least TLS 1.2 when accessing accounts configured to impose minimum confidentiality requirements.
The default minimum expected level of confidentiality for all new accounts MUST require successful validation of the server's certificate and SHOULD require negotiation of TLS version 1.2 or greater.
The updated recommendations in this document are based on RFC 8996, which formally deprecates TLS 1.0 and TLS 1.1; implementing TLS 1.2 or later is necessary to provide adequate confidentiality for email between MUAs and mail servers.