Unfortunately version 0.30 was not running on some Windows versions, so here comes fixed one. There is no need to update if you did not use Windows binaries.
You are downloading Wammu source code. Before you can run Wammu, you need to have installed python-gammu, Python and wxPython. There are also some optional requirements for additional features which are listed in INSTALL file in sources. This file also contains more detailed instructions about installing Wammu.
You are downloading standalone Wammu installer for Windows. If you want to use your system Python and install dependencies manually, please use pip tool to install Wammu.