The latest version available is: 3.00 (released on 28.09.2015)
The installer contains both x64 and x86 versions.
NOTE: There will be no future updates targeted for Windows XP users. In order to receive the latest updates in future, please upgrade to a newer operating system.
The latest version available is: 2.46 (released on 16.4.2014)
There's a version with web-based user interface that is currently available for Linux users.
See AirDC++ Web Client for more information and installation/download instructions.