How can I downgrade MDaemon 10.x to a previous version of MDaemon?

Unlike previous versions, you cannot install the old version of MDaemon over the top of a 10.0 installation, due to the numerous changes. The installer for 10.0 automatically backs up the old \App and \SpamAssassin folder, which you can use to downgrade to the previous version by following the steps below.

1. Download your previous version's installer from http://archive.altn.com/
2. Shut down MDaemon by going to the Windows Start Menu | Programs | MDaemon | Stop MDaemon
3. Open the Task Manager's Processes tab (Windows Start Menu | Run | type 'taskmgr.exe' | Select Processes tab) and verify the following MDaemon processes have stopped (note that if you have multiple processors, you may have multiple instances of some of these processes):
* MDaemon.exe
* CFEngine.exe
* MDSpamD.exe
* WorldClient.exe
* WebAdmin.exe
* ScanningProcess.exe (if SecurityPlus is installed)
4. Go to the MDaemon folder on the server. Note: The C drive is the default location, but it may be in a different location depending on the previous installation.
5. Rename (i.e. App_old) the following folders:
* App
* SpamAssassin
* WorldClient
* WebAdmin
6. Copy the your previous version's MDaemon\backup\(version)\App to MDaemon\App\
7. Copy your previous version's MDaemon\backup\(version)\SpamAssassin to MDaemon\SpamAssassin
8. Run the installer you downloaded and ensure you install into the same location MDaemon is already installed. Also, make sure to Disable (uncheck) Start MDaemon option at the end of the installation.
9. Copy the WorldClient.ini file from the renamed MDaemon\WorldClient_old to MDaemon\WorldClient
10. Start MDaemon by going to the Windows Start Menu | Programs | MDaemon | Start MDaemon


Reference:
http://www.altn.com/Support/KnowledgeBase/KnowledgeBaseResults/?Number=KBA-02126