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

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.