@Percy-Cox If you still have the old version of Music Maker installed I recommend you export each track as an individual WAV file and simply drag and drop them into a new Music Maker project. This will circumvent certain problems like missing instruments or effects which are no longer included in the current version.
Projects made in Music Maker 2021 or later should open fine in Music Maker 2024.
@Percy-Cox You should be able to download your old version in your customer account at Magix.com. Simply login with the same e-mail address and password you used to register Music Maker back then.
Be sure to register it to the same customer account or e-mail address you used back in the day. You can change the e-mail address in the account settings of you want to use a different e-mail address. You might be able to enter your old Music Maker serial number in Music Maker 2020 to unlock features.