OK, as it turns out, if you already have the Celestial installed, active or not, WordPress does not have the ability to upload and replace the existing theme with a new version. You have to unzip the new theme file, then manually upload the files to replace the existing theme files.
IMPORTANT: If you made any changes to the current Celestial theme “files”, overwriting them with the new version means you will lose your modifications made. However, if you have not made any changes to any files, you can overwrite them with the new one.
RECOMMENDATION: Before doing the above, I would recommend making a copy of your current theme files.