As long as the old version is found in your MakeMusic (was FinaleMusic) account, you're good.
Some of us going way back found that we had multiple accounts dating from back when we bought our copies then mailed in the cards plus whatever was going on at Coda back in the day complicated by email address changes through the years... In my case, I was buying my daughter's licenses when she was in school and her email changed a few times. What a mess! Sales can sort it all out through the Submit a request link at the top of the page. Nowadays, my kid and I each have one user account with only our individual licenses. Whew!