RockAway 13.1 "reference error: can't find variable fieldset"

I went to upgrade to Rockaway 13.1 to solve the Chatter component issues. When I clicked install in production I got this error. I did not proceed with the install just in case. Does this matter?

Looks like a bug with Salesforce’s Lightning-based Package Installer. Try using the non-Lightning-based package install process: remove the “newui=1” parameter from the Package Install URL:

I tried using your link above and received the same error. I don’t know if it matters. I still did not install just in case.