Multiple generations are not booting?

[CurlyMo]

You told me that the file XBian_2015.05.16_imx6.img.gz is actually XBian_Stable_rpi.img.gz. If you look at the list, you'll see that XBian_Stable_rpi.img.gz is the same as XBian_2015.04.04_rpi.img.gz. So your comments is incorrect in this sense.

Secondly, the reason we use this naming convention can be read here:
http://www.xbian.org/xbian-stable-release/

Thirdly, the installer just lists the versions available for a specifc platform.