Apple will roll out the iOS 9 update today, and this will include several important changes. Here is a list of some of these including, a checklist of what to prepare before downloading and updating your mobile devices.

The most talked-about iOS 9 update involves a significant improvement to Siri. Apple is introducing a "Proactive" functionality to the personal assistant, which borrows from the Google Now concept. In addition, Siri will now track usage so that it learns the time that the user will want an app, warn of traffic delays or pull up information from mail or the user's calendar, among other things useful to the user. The idea is that it will get better with time, with interactions tailored to the owner. 

Another change involves the way users multitask.  Like Android, it is now using a card layout. This change is also better appreciated in the iPad, where true multitasking is implemented, according to The Guardian. Here, users can run two applications at the same time, like one would see in several Android devices such as Samsung and LG.

Other notable updates include a change to the keyboard, UI font, an upgrade to the Notes app and a capability to track sexual activity, among others. Users will not be able to notice the changes after upgrading because iOS 9 feels and looks like its predecessor; they will start noting changes as they interact with the device since they are more subtle, aiming to polish the system rather than introduce change, according to The Independent.

There are a few things to check before upgrading to iOS 9 to ensure safe and secure outcome. First, users must determine if their device is compatible. Unfortunately, not all iOS devices are supported. It is expected that it will not work on devices before the iPhone 4S or the iPad 2. Then, it helps to back up your data and update all your installed applications.