What are the drawbacks of updating my iPhone 4s to the latest iOS? What are the advantages? With my phone plan, I cannot get the newest iPhone yet.
- more security
more features: quick reply, continuity (if you have Mac & Yosemite )
- it will run slowly
- you won't get a lot of the features that 5S and above have
- could decrease battery life
If you have experience with ssh and jailbreaking, I would say go ahead but make sure you can downgrade using ssh just in case you don't like it. However, if you don't even know what that is, I wouldn't recommend upgrading because there is no way to downgrade if you don't think you'll like it because apple already stopped signing ios7 and below.