To make the situation more curious, I would like to add my experience.
Within this forum there is the continuous statement to use Arduino 1.0.6 for the latest Vellemann firmware. This is the official statement from Vellemenn, any other work is on your own risk.
In fact, when using the next versions of the Arduino (1.1, 1,2) the compilation failed with a lot of warnings due to multiple redfinition of pins and an error due to improper variable declaration. This behavior was the major cause for me to work on the firmware and do my own modification.
For the later versions of the Arduino IDE this error doesn’t appear any longer, the original Vellemann firmware can be compiled with Arduino 1.5 and 1.6 without error messages (not tested with higher versions). It should be noted, that the resulting binaries have different sizes with respect to the compiled version with Arduino 1.0.6.
The transfer tool for the upload of the firmware is basically the same for all arduino versions, so there shouldn’t be any issue. I’m using the Arduino on a Linux machine without problems. Since I selected the Eclipse flavor “arduino-eclipse” for the software development, I’m using only the libraries from Arduino 1.5.7. Within this environment everything is fine and running.