What is a summary the main differences between the Arduino 1.0.x and 1.6.x IDEs? Why do some Arduino products, such as the LightBlue Bean, still require use of the 1.0.6 IDE?
I think Arduino's version history is a bit confusing. I'm not an expert but I think this explanation will help. First let's note that version 1.6 was released 2015.02.09. However, back in 2012, version 1.5 BETA was created and it remained in beta for several years. Meanwhile, the 1.0.X version evolved independently here's an excerpt from the changelog
- ARDUINO 1.0.6 - 2014.09.16
- ARDUINO 1.0.5-r2 - 2014.01.08
- ARDUINO 1.0.5 - 2013.05.15
- ARDUINO 1.0.4 - 2013.03.11
- ARDUINO 1.0.3 - 2012.12.10
- ARDUINO 1.0.2 - 2012.11.05
So you can see that 1.0.6 isn't as old as one may think. Many vendors probably chose not to develop their products against the 1.5 version (or branch) because of its beta status. 1.5 being in beta for as long as it did lends to a confusing version history. I did get the impression that LightBlue Bean is working on compatibility with 1.6.x because their getting started page mentions
Download and extract the Arduino app, version 1.0.5. We currently do not support newer versions of the Arduino IDE.