This release marks significant improvements in stability, compliance with current OTP versions, and enhanced capabilities with the addition of LMTP support.

Features

• Add LMTP support to the gen_smtp_client
  Author: Pablo Willian Suchewschy
  This addition includes support for the LMTP protocol, along with a dedicated test for the LMTP client.

• Document socket options
  Author: Oneric
  Updated documentation to clarify that tls_options is no longer filtered and to explain the use of socket options for newer OTP releases.

Bug Fixes

• Fix issues with gen_smtp_server_session compilation on OTP-28
  Author: Marc Worrell
  Resolved a compilation error for gen_smtp_server_session on OTP-28. This commit also includes updates to GitHub actions and CI environments by removing older OTP versions.

• Allow sender to immediately hang up after QUIT message
  Author: Marc Worrell
  Introduced the ability for the sender to terminate the session immediately after sending a QUIT message.

• Fix DATA response in smtp_server_example
  Author: ts-klassen
  Addressed errors in the DATA response handling within the smtp_server_example.

• Fix OTP 26 compilation failure
  Author: Thanabodee Charoenpiriyakij
  Corrected type specifications in handle_error to resolve compilation issues with OTP 26.

• Fix source links in documentation
  Author: Adam Millerchip
  Updated documentation links to ensure they direct correctly to relevant sources.

• Correct README instructions for IPv6 launching
  Author: rdtq
  Adjusted instructions to better clarify how to launch the server on IPv6.

• Fix parameter value encoding
  Authors: Maria Scott & Jan Uhlig
  Corrected parameter value encoding issues for better functionality.

• Fix CI environment compatibility
  Author: Chris Wögi
  Modified the CI setup to ensure that it functions correctly given that OTP 23 is not available on Ubuntu 22.04.

• Various improvements and simplifications
  Author: Marc Worrell
  Streamlined various implementations, including simplifying code related to message sending.