Programming Phoenix LiveView B9.0: The “Render The File Upload Field” section contains an unnecessary step as of Phoenix >= 1.7.3 (p. 145)

Pragmatic Bookshelf PragProg Customers
1

The book describes the process of adding multipart to the allowed attributes for the <.simple_form> component. As of Phoenix 1.7.3, this step is no longer necessary.

2

Indeed! You’ll see this change along with other upgrades in the upcoming new Beta book release.