If you are looking for a for your business or personal use, you should not rely on version 5.7. Instead, you should download and install the latest official stable release: hMailServer 5.6.x , which continues to receive updates for critical security vulnerabilities.
Windows Server 2012, 2016, 2019, 2022, or Windows 10/11 (for testing/local development). Framework: Microsoft .NET Framework 3.5 or higher. download full hmailserver 57