The design of the ORM changed substantially once, early in Django's history, when the "magic removal branch" landed. There are some notes on the new syntax that introduced here:
https://code.djangoproject.com/wiki/RemovingTheMagic#Codecha...That branch merged on May 1st 2006: https://www.djangoproject.com/weblog/2006/may/01/magicremova...
I've long found Django's commitment to not breaking too much at once inspiring. The release notes and upgrade guides are really solid.