...It runs on CPython on Unix and Windows under Python 3.7+. It is also known to run on PyPy 3 (python version 3.7+) on UNIX. It supports HTTP/1.0 and HTTP/1.1. Waitress now validates that chunked encoding extensions are valid, and don't contain invalid characters that are not allowed. They are still skipped/not processed, but if they contain invalid data we no longer continue in and return a 400 Bad Request. This stops potential HTTP desync/HTTP request smuggling.