I'm seeing that there is a 16.12.3 build out and I'm pretty sure that my Windows build is still 16.12.1, so does anyone know how to update my build, if I can?

KDEnlive was made for Linux, and most Linux distros have update systems.
As such to update the Windows version, you probably need to reinstall. Sorry.

Simple answer: ditch windows and use a real OS. If not linux, then buy a mac, or install freebsd, or anything. Sorry to be so blunt, but this is especially true with the recent windows "10" disaster, with sources too numerous to mention having proven that this travesty excuse for an "operating system" just collects your personal data and sends it to microsoft. And as a side note, the latest microsoft "offering" gives you no useful functionality which you didn't have in any iteration of this bloatware in the past 15-20 years.

Apart from the troll-ish OS discussion, back to the question:
building Kdenlive on windows is not an easy task for the moment, due the high number of multimedia/UI dependencies.

We have cross-compiled the 1st binaries from Linux (with MXE scripts). I am in the process of building an all updated archive (Kdenlive & all deps), but face several issues to solve in MLT & Kdenlive codes, due to evolutions everywhere...

I think we should prepare building Kdenlive from Windows using KDE "craft" tool (which handles dependencies), that would allow Windows users like you to be more independent in updating & contributing. If you have experience in packaging / fixing portability bugs, would you be interested to help? That would be a very useful experience for you, our project, and potentially many other people

Cheers,

Vincent