You would want to install the OS update before installing the newest version of Pro tools. Upgrading your OS won't destroy your licenses on the iLok, but you would want to download the newest drivers once you have updated. Also, you will need to install the newest USB drivers for your MBox for it to work properly. All of your sessions should open up without a problem. You may need to relink some data to make it work 100%, but it should be good to go.
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