Finale v27.1 allows converting of non-SMuFL fonts to SMuFL-compliant fonts as a document's default music font. However, this is limited to fonts that are provided with Finale by MakeMusic. For more info on fonts and a full list of fonts that MakeMusic provides, click here.
If you see the error below, this means that you are attempting to change a third-party legacy font to a SMuFL-compliant font as your default music font.
Swapping of third-party fonts is not supported in this situation because of the amount of possible variance between fonts (due to lack of standards for these fonts) and the issues this could cause during conversion to SMuFL.
Although is not supported, you can get around this. Go to Document > Set Default Music Font. Then choose a MakeMusic legacy font (Maestro, for example) and click OK. Once this has finished you can then go back to Set Default Music Font and convert to any SMuFL font you have available.