iPhone 5S was Apple's first smartphone with the Touch ID fingerprint home button and a 64-bit processor when it launched in 2013.
It was also the last new iOS phone to feature a smaller 4-inch screen, at least until the iPhone SE came out in 2016.
Today's 4.7-inch iPhone 7 and 5.5-inch iPhone 7 Plus are meant for people with larger hands and bigger wallets. Thankfully, you can still find the iPhone 5S through online retailers at a discount. Let's see if it's still relevant.
When it was first unveiled, the iPhone 5S looked a lot like the iPhone 5, even though it went much further under the hood. We'd been there before with the iPhone 'S' conundrum: a new phone comes along, taking the shell of the previous model, adds some new bits and pieces, and then claims to be an entirely new phone – and we've just seen it again with the iPhone 6S and even the iPhone 7.
Which it was, of course. But also wasn't. Well, mostly was. It's the kind of move that only Apple can pull off with any kind of conviction: the notion that it can take the same chassis, have a little tinker, throw in a new CPU, slightly better battery and camera, and call it an all-conquering device.
The jump from the iPhone 5 to the iPhone 5S was nowhere near as significant as the leap to the iPhone 6 and 6 Plus – Apple's handsets changed notably inside and out at that point, and their release should give you serious pause if you're looking at buying an iPhone 5S right now.
The 5S started out as an expensive smartphone, even on monthly plans, although thankfully the price has fallen considerably as the handset has gotten older.
You can find it pre-owned for as little as $250 in the US (about £200, AU$330) at SIM-free prices. That beats the last official list price from Apple that had it at£379 (US$450, AU$749) for 16GB, and £419 (US$499, AU$829) for 64GB.
If you want a larger capacity iPhone, you'll want to either look for second hand models of the iPhone 5S, or make the leap to the iPhone 6S or iPhone 7, the latter going all the way up to 256GB if you're willing to spend a lot of money.
For its time though, the 5S was a big jump forward, and it's still in credit now: whether it's the Touch ID home button (which is excellent, more on that later), the jump in CPU power over its predecessor, the fact the camera was, once again, improved, or the new iOS 10 software it's now running, the iPhone 5S saw Apple attempting to bring as much as it could to the party without having to redesign the whole concept all over again.
There are many that think releasing the same design twice is cheeky, and there are others who realize that sometimes there's no need for change. It's easy to fall into the former camp, and while Apple will happily point out it's not forcing anyone to buy its phones, it's acutely aware the competition is now scarily strong and it needed to bring its best to stay relevant.