One way to keep track of meta model changes is to export the meta model. There are two options.

Automated Export Using the swExport Tool

For automated export, you can utilize the swExport tool. Below is an example command line for exporting only the meta model. It could, for example, be incorporated in to scheduled back-up processes.

Example Command

swExport.exe XmlFileName=c:\temp\MMExport.xml ExportMetadata=true ServerName=sys7 ServerPort=1234 ServerUserName=username ServerPassword=password

Example Output

Tip: Notepad++ offers a plugin called XML Tools which provides an option for formatting XML files which makes the files easier to read: 

Export Using the swArchitect Client

The XML Export... option on the Metadata tab enables Architect users to export the meta model of the current database into a SystemWeaver XML format that can be imported in to other SystemWeaver databases.
The dialog gives you the option to add an Export Description to the exported file, before saving the meta model:

The Include config-items option can be used for including the config items* of the database in the export.
Click Save to save the meta model to a SystemWeaver XML file.

* Note that technically config items are not part of the meta model, since they are in fact a subtype of Item. Config items, however, serve to configure a database, much in the same way as the meta model.