Apple released two new minor updates for older iOS devices, iOS 12.4.2 and watchOS 5.3.2 for Apple Watch Series 1 and 2.
The iOS 12.4.2 update is only for the first-generation iPad Air, iPad mini 2, iPad mini 3, iPhone 5, iPhone 6, iPhone 6 Plus and first-generation iPod Touch. As mentioned above, watchOS 5.3.2 is for Apple Watch Series 1 and Apple Watch Series 2, devices running watchOS 6 are not yet updated.
The new updates introduce some security fixes, therefore the update is strongly recommended for all compatible devices.
To update your iOS device, we suggest using OTA since is the shortest and easiest way to perform the process. All you have to do is open the Settings application, go to General and then Update Software; your device will start searching and downloading the new update, which will be covered and without security vulnerabilities.
As for Apple Watch, you will have to open the Watch app on your iPhone, then enter the General menu and then Software Update to start the download.