With the release of iOS 9.3, multiple reports have emerged complaining about older devices getting stuck at the Activation Lock screen. Although, with this new build of iOS 9.3, iPad 2 owners should now be able to update or restore their devices in order to continue using them as usual.
However, iPhone 5s and older or iPad Air and earlier users stuck in this issue can try Apple' s instructions on how to solve the issue, which recommends removing Activation Lock via iCloud or attempting to enter an Apple ID or password through iTunes.
According to Apple "Updating some iOS devices (iPhone 5s and earlier and iPad Air and earlier) to iOS 9.3 can require entering the Apple ID and password used to set up the device in order to complete the software update"
The Updated iOS 9.3 is now rolling out as a free update to the iPad 2 and can be downloaded via iTunes. With other older iOS devices to get it in the coming days.