How can I use the EV3 educational firmware instead of the retail version?
Update: LEGO Education software is now available for free.

https://education.lego.com/en-us/downloads/mindstorms-ev3

Original answer:

You need to purchase the EV3 Education version of the software. It includes the EV3 Education version firmware.


EV3 Education Software (single user licence)
EV3 Software v1.1 Update (includes v1.06E firmware update)