Probably you need to get Finale v27.

Peter is correct—26 will not run over Sequoia. The $149 crossgrade path to Dorico is still open and includes a license for v.27.

https://www.steinberg.net/dorico/finale-crossgrade/ 

You want to jump on this quickly. 

Although there is no support for 27 over Sequoia, I and others are running it without complaints.

Tahoe, on the other hand, is problematic. 27 will work sorta' kinda'. Files open and you can get things done but some functions require workarounds. 

Thank you Peter and Mike! I just realized that I do have Finale v27.  Will it open in Sequoia?