Upgraded from an Upgraded Adobe Acrobat Version

I purchased Adobe Acrobat XI in 2014 and upgraded it in 2017. Now I've moved that to my new laptop and purchased the upgrade to Adobe Acrobat 2020 Standard. During installation it's asking me for the serial key for one of 3 versions in 2017 (including Standard 2017), but it won't accept the serial key for the original XI version from 2014. Where is the other serial key for the 2017 upgrade? How can I make this work? Thank you.