4.4.1

Bug Fixes:

• Fix a bug where pip-compile would keep outdated options from requirements.txt (#1029). Thanks @atugushev
• Fix the No handlers could be found for logger "pip.*" error by configuring the builtin logging module (#1035). Thanks @vphilippon
• Fix a bug where dependencies of relevant constraints may be missing from output file (#1037). Thanks @jeevb
• Upgrade the minimal version of click from 6.0 to 7.0 version in setup.py (#1039). Thanks @hramezani
• Ensure that depcache considers the python implementation such that (for example) cpython3.6 does not poison the results of pypy3.6 (#1050). Thanks @asottile

Improved Documentation:

• Make the README more imperative about installing into a project's virtual environment to avoid confusion (#1023). Thanks @tekumara
• Add a note to the README about how to install requirements on different stages to Workflow for layered requirements section (#1044). Thanks @hramezani