I have written two books on the Walkera Runner 250s, the Walkera Devo 7 Configuration Guide and the MultiWii 2.4 for the Walkera Runner 250. I wrote those books out of frustration, first on the Devo 7 Transmitter as it is incredibly hard to understand the Users Guide. While the manual is written in English, it is clearly a translated English and sometimes the translation does not come across as it should. I know see how other countries are challenged when they have to read English translations. I wrote the MultiWii 2.4 for the Walkera Runner 250 because the factory firmware was so bad it basically made the Runner 250s into lawn darts and very expensive ones at that.
I am starting to see people use the MultiWii 2.4 for the Walkera Runner 250 and upgrade their quadcopters to the latest firmware. One person, Mikerman50 on YouTube, in particular has posted a cool video of him connecting his Runner 250 up to a the HM-10 Bluetooth Module and is now able to have complete control over his quadcopter with a MultiWii GUI on his Samsung S4. I did some testing as well with an application that I installed on my iPhone so you can get MultiWii GUI applications on the smart phone of your choice.
MultiWii 2.4 as what is called the MultiWii Serial Protocol and you can actually program GPS Waypoints into the quadcopter for an automated flight. You can also have several PID profile settings so that you can tune your quadcopter for a racing or a more gentle flight for aerial photography.
I am looking forward to more adoption and more experimentation by the readers.