Will updating my iPhone 4 make it run slower?

Right now It says I'm on 7.1.2 and I want to update it but I'm afraid it will make it slower because its older.

IOS 9 is faster and saves more battery don't worry!

My iPod touch 4 became so slower after the update…

It may become slow cause newer verson of IOS wants high hardware performance which is unavailable in your phone.

As long as it works fine then I would keep it as is just because its alot older hardware.

The iPhone 4 can't go past iOS 7.1.2; there's no later update that works with it.

Umm… Time to UPDATE the phone to a NEWER MODEL. I'm sure you can find a new deal on a new one.