Legacy smartphones by Apple gained speed and performance bumps with the release this week of iOS 9.2.1. Owners of iPhone 4S, 5 and 5S should experience the smoother of their devices immediately after updating to the latest mobile operating system version, a new report said. 

Apple Insider pointed to a new YouTube clip from iAppleBytes that showed older iPhone models saw boosts on boot up time and faster app loading. The video compared iOS 8.4.1, which many believed is the best version available for legacy iPhones, and iOS 9.2.1 and proved that the former iOS build can be retired thanks to the latest version.

Like Us on Facebook

For iPhone 4S users, applications seem to launch faster and behave better than with the previous versions of Apple's mobile OS. However, booting up the 4S on iOS 9.2.1 remains relatively sluggish, the report said.

On the other hand, faster boot up time is the key benefit of iPhone 5S users that will update to the latest iOS as Apple Insider noted on its reports that the iAppleBytes clip has suggested that the 64-bit mobile processing chip that came with the device is key factor on the speed bump. As expected, the nearly three-year old iPhone 5S also increased its general performance level owing to the firmware update.

And with the release of iOS 9.2.1, Apple has intended too to plug the security holes that were detected in the previous versions, including the vulnerability that would permit hackers to access sensitive information stored on an iPhone when connected to a public or unsecured Wi-Fi.

The performance and security improvements, per BGR, should convince iPhone users to step up and quickly install iOS 9.2.1. Apple's latest move should greatly benefit users who opted to stick with the iPhone 4S or 5S up to this time, the report added.

But jumping to the latest iOS build will also mean that there is no return trip to the older versions. Specifically for legacy iPhone users, they will be locked out from iOS 8.4.1 and will have to live with iOS 9.2.1 even if something goes wrong.

In such event, the only recourse is to wait out for iOS 9.3, which is already in beta release and should be out soon or for take on the jailbreak path, which is not for everyone.