Apple has silently updated older versions of iOS with new builds. The two new iOS builds include iOS 9.3.6 and 10.3.4. The builds are specifically meant for older iPad and iPhones that cannot be updated to the latest iOS.
The older versions of the iOS were released alongside the iOS 12.4. The iOS 9.3.6 is for the cellular version of iPad Mini, iPad 2 and iPad 3 and the iPhone 4s while the iOS 10.3.4 is for the iPad 4 (cellular version) and iPhone 5. As expected the updates address a slew of security issues and also include a fix for GPS bug which affected location accuracy and also caused incorrect date and time update.
In order to install the update on eligible devices, head over to Settings app. In the next step go to Settings>General>Software Update. Follow the onscreen instructions and make sure that your device has sufficient charge.
Apple rarely releases updates for discontinues operating systems. However, iOS 9.3.6 and 10.3.4 seem to be directed at fixing security issues which could have put users in danger. It is good to see that Apple values security and issues patch for older devices.