There is a new release of MDaemon, Version 19.5.1 please see below for the list of Special Considerations and Changes before installing this update.
If you have any questions about this release please feel free to contact us on firstname.lastname@example.org
Latest download available from here
 The LetsEncrypt functionality has been updated to use ACME v2. This update is required because LetsEncrypt is discontinuing support for ACME v1. PowerShell 5.1 and .Net Framework 4.7.2 are now required in order to use LetsEncrypt.
-  fix to ActiveSync – clients that required previous approval need to be re-approved
-  fix to ActiveSync – Unable to login when using domain and full email address
-  fix to Mobile theme – Sending plain text emails results in an empty message body
-  fix to Mobile theme – Cannot download attachments in folders other than Inbox
-  fix to Mobile theme – Cannot add inline images to a new message
-  fix to Webmail – Images in the default client signature may not be displayed in Webmail
-  fix to MDRA – When adding an image to a Default Client Signature, the image file is placed on the root of the C drive
-  fix to licensed features may be disabled after renewing an MDaemon registration key that had been switched to trial mode
-  fix to memory leak in DAV server if folder contains over 1000 events or contacts