# Guides on backward compatibility & deprecated practice

`Setuptools` has undergone tremendous changes since its first debut. As its development continues to roll forward, many of the practice and mechanisms it had established are now considered deprecated. But they still remain relevant as a plethora of libraries continue to depend on them. Many people also find it necessary to equip themselves with the knowledge to better support backward compatibility. This guide aims to provide the essential information for such objectives.

- New and Changed `setup()` Keywords
- Specifying dependencies that aren’t in PyPI via `dependency_links`
- The Internal Structure of Python Eggs
- Easy Install
- Understanding the `zip_safe` flag
- Automatic Resource Extraction
- Distributing Python Modules (Legacy version)
- Porting from Distutils
- “Eggsecutable” Scripts
- Running `setuptools` commands