You get version 1.0.3 (and beyond) automatically and safely.
: A new horse companion that helps in battle and can be customized with various colors and manes. Miitopia -NSP--Update 1.0.3- -2-.rar
: After installation, the game's version number on the home screen (viewed by pressing the button) should reflect version 1.0.3. Important Safety and Legal Notes Source Caution You get version 1
Here is a story concept centered around the arrival of this specific update in the world of Miitopia: The Case of the Vanishing Faces: The 1.0.3 Patch Miitopia -NSP--Update 1.0.3- -2-.rar
Then, a notification popped up from the system tray:
The specific file name provided suggests a pirated version of the update.