When the new version of Metashape is released it is possible to update the application. To update Metashape Professional to the newest version perform the following actions depending on the OS:
Download new installer from http://www.agisoft.com/downloads/installer/, then install it to the same folder where to previous version has been installed, re-start the application - the license should be used automatically. In case you have installed new version to another folder on the same computer, copy valid license file (.lic) from the older version folder to the new one.
Download new version package from http://www.agisoft.com/downloads/installer/, unpack it to any folder on the computer where Metashape Pro has been already activated, then put valid license file (.lic) from the older version folder to the new one.
Download new installer from http://www.agisoft.com/downloads/installer/, unpack it and move PhotoScanPro application bundle from DMG archive to any desired location on the computer where Metashape Pro has been previously activated, copy valid license file (.lic) from old MetashapePro application bundle contents to the new one and re-start the application.
To open the contents of the application bundle in the Finder window you can right-click on the MetashapePro.app and choose Open application contents option - it should display the /Contents/ folder inside the bundle, the license file should be put to MetashapePro.app/Contents/MacOS/ directory.
In case the license file from the old installation is lost for some reason, you can just input the same license key to the Help Menu > Activate Product dialog and the same license file will be automatically received and put to the required directory.