Night Shift not showing up on IPhone settings?

I just updated my iPhone 5 to iOS 9.3. The problem is when I check under Display and Brightness on settings it isn't there. I don't know how to fix it. Do I have to enable or disable something else on settings to use night shift? Or how do I get it on settings?

It's not a bug, your iPhone is more than capable of running this feature (f.lux has done it on jailbroken devid s for a long time now) but Apple only wrote it for 64bit capable devices, meaning 5s and newer, so your iPhone isn't compatible with this and doesn't have the feature.

If you want it I suggest you wait for a 9.3 jailbreak to be released by pangu or taig really soon (no date given) and install f.lux (from who Apple ripped the idea for night shift off). Do not believe any website who says it has the hailbreak right now, they're lying. Pangu and taig are probably waiting to see if Apple will fix the 9.3 bugs with another build or another version and wait for that so Apple doesn't patch their exploits right away. It's believed that this is the last version of iOS before iOS 10 so if they wait to see Apples response to the bugs and release it after, their jailbreak would be effective until iOS 10.