Secure Mail Gateway Changelog – Relution Customer Hub

Secure Mail Gateway 26.0.7

Thu, 22 Oct 2026 00:00:00 +0200

Breaking change with SMG 26.0.7: From SMG version 26.0.7, the Secure Mail Gateway requires additional configuration when the Exchange server is reachable using a private IP address range (RFC 1918 →). See Forwarding to private IP addresses →

Fixes

Important security fixes and hardening improvements [REL-14324]
Breaking change with SMG 26.0.7: The Secure Mail Gateway requires additional configuration when the Exchange server is reachable using a private IP address range (RFC 1918 →) [REL-14327]

Secure Mail Gateway 26.0.6

Thu, 17 Sep 2026 00:00:00 +0200

Fixes

Incoming HTTP headers are now correctly treated as case-insensitive in all cases, which avoids potentially duplicated headers in the forwarded request [REL-13556]

Secure Mail Gateway 26.0.5

Thu, 20 Aug 2026 00:00:00 +0200

New

Show more useful info about custom CA certificates added to the trust store [REL-12991]
Show more useful info when a connection is rejected due to an untrusted server certificate [REL-12991]
Basic HTTP exchange errors are now also visible when using HTTP/2 [REL-13245]

Updates

Native headers strategy is now the default [REL-12991]
Default HTTP post-size limit is now 1 GiB [REL-12991]
Premature transfer completion is now logged [REL-13245]
Log Exchange server’s status response code when a message is rejected [REL-13245]
Logs now show basic activity rather than nothing for successful transfers [REL-13245]

Fixes

The connection of a transfer that terminates prematurely is properly disposed [REL-13245]

Secure Mail Gateway 26.0.4

Tue, 04 Aug 2026 00:00:00 +0200

Updates

Update code style to fix formatting issues when switching between projects [REL-14911]
Update publishing process to docker hub to meet latest security requirements [REL-14912]

Secure Mail Gateway 26.0.3

Fri, 10 Jul 2026 00:00:00 +0200

Updates

Support for self-signed certificates and proxy settings [REL-12714]

Secure Mail Gateway 26.0.2

Tue, 30 Jun 2026 00:00:00 +0200

Fixes

Fix wrongly handled 404 responses [REL-12560]

Secure Mail Gateway 26.0.1

Wed, 17 Jun 2026 00:00:00 +0200

Updates

Expose health endpoint [REL-14913]

Secure Mail Gateway 26.0.0

Wed, 27 May 2026 00:00:00 +0200

New

First version as a standalone service; the Secure Mail Gateway was previously part of the Relution server [REL-2856]