There were some big changes in Arduino IDE 1.5.x and later, which made parts of the Xronos Clock code incompatible. Fortunately it wasn't to difficult to port firmware to new IDE and I'm happy to announce that version that works with latest Arduino IDE (currently 1.6.5) is here. There are few important things you need to be aware if you plan to use source code. Some old libraries (Time) as well as Mightly1284p hardware definitions became incompatible with IDE 1.6.x so you'll need to update those as well. Mightly 1284p platform can be downloaded here. Just remove old folder form our [SketchFolder]\hardware and replace with new one. Additionally grab a new version of Time library here. As for the code itself, there were really minor changes. Namely all PROGMEM variables in Font definitions had to be changed to "const unsinigned". Grab source code here. Update: If you got version 2.14 please upgrade to 2.15 ASAP. There's a serious bug in 2.14 that prevents you from going to User Talk Items menu. 2.15 fixed it.