Apple has worked hard in developing patches to cover up for the vulnerabilities it was exposed. These vulnerabilities made it easy for jailbreak groups to get root access and get into the file system and manager of iOS devices.
According to Neuro Gadget, the term jailbreak refers to the process by which the software restrictions on iOS devices are removed. The removal of restriction allows getting access to the file manager and system file. As a result, users can download applications, themes and extensions unavailable in the Apple App Store. Jailbreak works on all iOS-based devices that include iPad, iPod touch, iPhone and generation 2 Apple TV.
According to The BitBag, Apple users seem to be asking for jailbreak tools, but jailbreak groups have not got much of success after iOS 9.0.3. Though, Luca Todesco displayed a screenshot of Cydia running on iOS 9.2.1 on Twitter, he did not release the jailbreak tool to general public. He also stated that jailbreaking iOS 9.2.1 was very difficult, a reason good enough for jailbreak groups Pangu and TaiG not to release jailbreak versions for 9.2.1.
This is the probable reason why jailbreak experts are asking users to avoid upgrading their phone to latest versions and downgrade it to iOS 9.0.2. Doing so, users will not be experiencing any restrictions on their devices and they'll be able to enjoy their devices with third party restricted stuff otherwise not downloadable. But with Apple stopping to sign iOS 9.0.2 firmware, downgrade option does not seem to work for users.
According to Christian Today, two jailbreakers claim to have broken iOS 9.3's earlier beta versions, which is not available to public as yet. If rumors are to be believed, Apple will release iOS 9.3 any time before March 21. With this planned release, it will be interesting to see how jailbreakers work with iOS 9.3.