South will not be available in Django 1.7. Django 1.7 migrations have been developed by the same person that has developed South and can be see as an official successor to South. Therefore you have no choice but to use the new migrations.
Here's a link to the Kickstarter campaign which includes all conceptual information about this: https://www.kickstarter.com/projects/andrewgodwin/schema-mig...
Here's a link to the official docs describing how to use migrations and the upgrade path from South: https://docs.djangoproject.com/en/dev/topics/migrations/