I figured that once I started pasting and checking code like: """ if sys.version_info >= (2, 3): # sick off the new hex() warnings, and no time to digest what the # impact will be! import warnings warnings.filterwarnings("ignore", category=FutureWarning, append=1) """ into the Mozilla source tree, it was time to start digesting! Unfortunately, a simple answer seems to allude me whenever it is brought up here. So, to cut a long story short, I have lots and lots of script generated, then often hand-edited source files with constants defined thus: SOMETHING = 0x80000000 Which generate a warning telling me that this may become a positive long in Python 2.4. All I really care about is how my C extension code, which does: PyArg_ParseTuple("ilhH", ...) // Take your pick is going to react to this change? (There are similar warnings for certain shift operations too, but I believe they will all boil down to the same issue) People using the win32all extensions are unlikely to be happy with the screenfulls of warning generated. I know I'm not <wink>. But I don't know what to do. I know I can suppress the warning either using the code I have above, or simply by appending an L to each of the thousands of constants, or even converting them all to decimal. But if nothing is going to change from the POV of my C extensions, then changing all these constants just to suppress a warning seems overkill. Any suggestions for me? Thanks, Mark.