According to Apple "iOS 9.3.4 provides an important security update for your iPhone or iPad and is recommended for all users". Unfortunately, with the release of this update, Apple has blocked the exploits used to jailbreak your iDevices, therefore it is recommended to stay away from the company's latest iOS release if you want to keep your Jailbreak alive.
However, if you accidentally updated to iOS 9.3.4 and lost all of your Jailbreak tweaks, you can downgrade your iDevice from iOS 9.3.4 to iOS 9.3.3 and perform the Semi-tethered Jailbreak using Pangu's Jailbreak Tool through your PC or Mac or even go the mobile way and jailbreak your device without a computer.
iOS 9.3.4 is now rolling out as a free update through Software Update or can be downloaded via iTunes to all supported iPod Touch, iPhone, and iPad devices.
