Migrating a codebase to Python 3 takes some thought, but it's worth the effort. In this talk, I'll discuss the ins and outs of migrating a real Python web application to Python 3. I'll discuss motivations for upgrading your codebase, the challenges you will face, and considerations you will have to make. A focus will be made on testing with continuous integration, advice on how to avoid problems resulting from the differences between Python 2 and 3, and lessons on how Python 3 will help you to write better code.