Go to settings, about, software information, more, then click build number at least 10 times. Until it says at the bottom you are a developer.

Sent from my HTC6525LVW using xda app-developers app
PREVIOUS DEVICES
Droid DNA [VZW] SOLD
DINC [VZW] Retired
DINC 2 [VZW] Smashed
Rezound [VZW] Sold
M7 [VZW] Retired to Father

ASUS Transformer Pad Infinity TF700T [Wifi] [smashed/returned]
Asus VivoTab [Wifi] [returned]
Nexus 7 [WIFI] [sold]


CURRENT DEVICES
HTC M8 STOCK