Before releasing new features for a certain module, usually, there will be a beta version to find potential bugs before releasing a stable version.
To update to a new beta version, e.g. for debugging the software, open thaTEC:Core and make sure that the update database of thaTEC:Core is up-to-date by checking for updates via the menu bar "Modules" => "Check for updates" or by pressing Ctrl+U.
Afterwards, right-click on the module you want to update and select "Update" => "Update to newer beta version"