Python 3 preparation: use // and __truediv__ as needed. Tool-assisted patch. Those divisions that I thought must be integer floor divisions and rely on Python 2 integer floor division semantics are changed to use // (if any are actually meant to be floating-point divisions, that would break things). One __div__ method is changed to __truediv__ (with __div__ = __truediv__ for Python 2 compatibility).

#!/usr/bin/env python

# Roundup requires Python 2.7+ as mentioned in doc\installation.txt
from __future__ import print_function
VERSION_NEEDED = (2,7)

import sys
if sys.version_info < VERSION_NEEDED:
    print("Content-Type: text/plain\n")
    print("Roundup requires Python %s.%s or newer." % VERSION_NEEDED)
    sys.exit(0)