[Answer]-Upgrading Django from 1.4 to 1.5 — url tag changed?

Yes, you are reading it correctly. The change is covered in the release notes

The change might be inconvenient, but it makes the url tag consistent with others, and allows you to use variables as well as strings as tag arguments. There was an option to use the new style tag in Django 1.3 and 1.4 to allow users to prepare for the change.