On the portable version, when SublimeText tries to update it requires administrative permissions, which I do not have. I am therefore unable to update
I don't have admin privileges either, so I just download the new portable zip file for each new release. Open the zip file and your portable installation directory in two separate windows (make sure Sublime is closed). Delete all the files and the Packages directory (make sure you keep Data!
), then copy the files from the zip into the Sublime directory. Restart Sublime, and you should be all set.