Maintaining compatibility between versions of Python is a challenge. It may add a lot of additional work depending on the size of the project, but is definitely doable and worth doing. For packages that are meant to be reused in many environments it is absolutely a must-have. Open source packages without well-defined and tested compatibility bounds are very unlikely to become popular, but closed third-party code that never leaves the company network can also greatly benefit from being tested in different environments.
It should be noted here that, while this part focuses mainly on compatibility between various versions of Python, these approaches apply for maintaining ...
