If you have the Desktop program you really don't need to upgrade to Home & Business. All the Desktop programs have the same forms. You just get more help and guidance in the higher versions. So you can keep Premier.
And you can open or transfer the .tax2020 file in any Desktop version. So yes you can transfer the .tax2020 file from any version into any version next year. And you can use the same file in either Windows or Mac programs.
