Releasing new features after one year, most visible improvements are in the SMSD.
You are downloading Gammu source code. To compile it you need some development environment for your platform and CMake tool to configure the sources. 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 compiling Gammu.
This source tarball contains Gammu command line utility, libGammu library and Gammu SMSD.
07691cfbf082038b6d8d4ad418ac34c983de551902b1cbd777f09350657b8a9f
dea9e0792d1507670b24fe8f4e2e9f006037bac4d6cf0dfda9129c63ceb42f26
a760a3520d9f3a16a4ed73cefaabdbd86125bec73c6fa056ca3f0a4be8478dd6
52f07be8b12eb668b0afe4dc9e3880fcbd822f503dc3d1d6a9ed6474c99cf89b
You are downloading Gammu installer for Windows. There is 32-bit version, 64-bit version and 32-bit version compiled with MSVC 9.0 to be compatible with Python 2.7.
You might need to install Visual C++ Redistributable Packages to run Gammu.
55f539a700a060726c79f9959f3b7bd0033b984a82a20e265b143c1c76eb9a47
beba51624b3b9d478fbec3dd4c248afc87b3a34603295908d67c6355bcbb9029
869e690bf1e1c243440000d4f4d851d730597b3170854f51fab1ee5edda55e20