2020 TT Premier for Mac OS requirements

I just purchased 2020 TT Premier for Mac. When loading a message said the program would not function starting January 2021 unless the OS upgraded to Catalina or higher. I now have OS Mojave 10.14.6 and for other reasons will not upgrade to OS Catalina or higher. 

 

Please advise if this limitation correct and what recourse possible.

  • Equipment: MacBook Air 13in. early 2015
  • Memory 8 Gigabyte
  • OS Mojave 10.14.6 

Thank you