Glad it worked out. If I might suggest something else... if you want this to be a compiled executable you might want to consider switching out of python to a compiled language as creating an executable out of a python script (just IMHO) kinda defeats the purpose of it being an interpreted language.
You may want to consider trying VB.NET since the language isn't complete different syntax wise to python and this would probably SIGNIFICANTLY reduce the size of the updater along with other various benefits... but up to your consideration obviously. Issue there being then people would have to install the .NET framework on their computers which is quite sizeable though I would be surprised if a large amount of the people here didn't have .NET already installed.
Edit: C, C++ or whatever if you're familiar with any compiled languages. Only mentioned VB.NET since to my mind it's probably one of the closer related languages syntactically.
Not sure how controversial speaking of such things are on these forums