I am not a MAC user, however I did locate the following info on the MAC Board on the Norton Forums: - it does appear to be old:
I saw that post. After Norton put up a window telling me that I needed to uninstall all Norton files. Which I did. I do not have an option of updating at that time. I just tried again to download from Xfinity. This time the download installed. I opened Norton and clicked on the live update option, and it ran for a while, finally came up with a dialog box "Norton Internet Security is unable to continue. Please restart your Mac to stay protected. If the problem still persists click here." When I tried to restart the Mac, Norton had processes running. When I click on the link, I get the window telling me to uninstall Norton. I did a force quit on Norton, rebooted, and when I open Norton it says everything is wonderful. But I don't dare do a live update.
At no time were any "Free Upgrade" messages displayed.
Perhaps if you post on the Norton for MAC Board on the Norton Forums, you can get a better answer. You can post there or you can wait and see if anyone comes along here that uses a MAC and has an answer. Sorry I was not more help.
<EDIT> Just spotted this thread rferring to Comcst and High Seirra.
Norton for mac available on the comcast website is compatible with Mac OS high sierra. The websit system requirement has not been updated yet but we have informed comcast already and this should change soon.
Please do run a live update and see what happes.
Running live update did not solve the problem, but contacting Symantec and having a technition take control of my computer doing all kinds of downloads and reinstalls with specific file deletions did. The technition was able to install the software, and it only took about an hour. I'm happy now, I feel protected again.