MacRumors published a story that Safari 15.1 beta is now available for macOS Big Sur and macOS Catalina.
Safari 15.1 Beta Now Available for macOS Big Sur and macOS Catalina
Apple on late Thursday seeded the first beta of Safari 15.1 for macOS Big Sur and macOS Catalina to developers for testing.
Safari 15.1 Beta Now Available for macOS Big Sur and macOS Catalina