Add news entry for upgrade-strategy
- **DEPRECATION** ``--default-vcs`` option. (#4052)
- **WARNING** pip 9 cache can break forward compatibility with previous pip
versions if your package repository allows chunked responses. (#4078)
+- Add an ``--upgrade-strategy`` option to ``pip install``, to control how
+ dependency upgrades are managed. (#3972)
- Add a ``pip check`` command to check installed packages dependencies. (#3750)
- Add option allowing user to abort pip operation if file/directory exists
- Add Appveyor CI
