hMailServer 6.0.0

Released 12 June 2026 6.0 series

This is not the current release. hMailServer 6.3.3 is the one to install unless you need this exact version.

Downloads for 6.0.0

Windows

Windows 10 (version 1607 or later) and Windows 11, or Windows Server 2016 and newer; 64-bit only. Run the installer as an administrator: it upgrades an installation older than this version in place, and it cannot go backwards — an older server refuses a database a newer one has upgraded, so back up the database and the data directory first. It is not Authenticode-signed, so Windows names an unknown publisher and SmartScreen warns before it will run it.

  • hMailServer-6.0.0-B4-x64.exex64 · 7.8 MB
    Download
    SHA-256b914ae90ba19…8ffc1518

What’s new in 6.0.0

hMailServer 6.0.0 (x64) - production release, build 4.

Full release notes for 6.0.0

Build 4 fixes a fatal installer defect: build 3 bundled VS2019-era VC++ runtime DLLs which the service loaded instead of the current ones, crashing it at startup (access violation in msvcp140.dll) on fresh installations. The installer now ships the matching v145 (14.51) runtimes and no longer bundles the obsolete 2015-era UCRT (included in Windows since Server 2016 / Windows 10). Build 3 also fixed MySQL/MariaDB database creation (script line-ending handling) and bundles libmysql.dll.

Validated by the full regression suite: 898/898 tests passing, zero failures, run against a MariaDB (MySQL backend) instance - including live SpamAssassin, ClamAV (real EICAR detection), DMARC against live DNS, and TLS 1.2/1.3 end to end.

Highlights of 6.0: OpenSSL 4 / TLS 1.2+1.3, MTA-STS, DANE with in-process DNSSEC validation, ARC sealing, Ed25519 DKIM, ACME (Let's Encrypt) built in, REST admin API, Prometheus metrics, IMAP MOVE/ID/SPECIAL-USE, PBKDF2 password hashing, 64-bit only, VS2026 toolchain.

See the README for upgrade notes and the full feature list.

Release facts

Version
6.0.0
Packages
1Windows, x86-64
Installer SHA-256
b914ae90ba19…8ffc1518hMailServer-6.0.0-B4-x64.exe

Every file in 6.0.0

Full SHA-256 of each file as recomputed on this server. Nothing in this release is signed — the signing workflow came later — so the hash above is this server’s own recomputation rather than a check against something the project signed.

FileWhat it isSizeSHA-256Signature
hMailServer-6.0.0-B4-x64.exeWindows installer · x647.8 MBb914ae90ba191e24fb9efd82c77db5aa6f1074aacf4390984284e43c8ffc1518—