Intuit University of Twente Mozilla arm Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS) are widely used to protect data exchanged over application protocols such as HTTP, SMTP, IMAP, POP, SIP, and XMPP. Over the last few years, several serious attacks on TLS have emerged, including attacks on its most commonly used cipher suites and their modes of operation. This document provides recommendations for improving the security of deployed services that use TLS and DTLS. The recommendations are applicable to the majority of use cases. This document was published as RFC 7525 when the industry was in the midst of its transition to TLS 1.2. Years later this transition is largely complete and TLS 1.3 is widely available. Given the new environment, we believe new guidance is needed.