You can update your current 1.4 or 1.5 installation to 1.5 RC 1 by using the built-in patch mechanism (make sure you switch to the Canary channel first, if necessary.)

BUT YOU MAY NOT WANT TO DO THAT. Patch-updating to this new version will replace your existing stable installation with a preview version. Instead, you can download a separate installation of 1.5 from the Android Studio 1.5 RC 1 page. You can keep 1.4 and 1.5 installed side by side; they use separate settings and cache directories.

If you run into problems, be sure to check the Known Issues page which we'll update as necessary.