I have Kali, release 17.1, 'installed' on a USB thumb drive. I have enabled the persistence capability and have some files stored that I regularly refer to.

Now that Kali release 18.1 is available, I am interested using the newer version. However, I would prefer to update the existing installation as opposed to starting from scratch. Is this possible? If so, would you please point me to the appropriate documentation.

Thank you.