Back in June 2024 at WWDC, Apple announced iPadOS 18. The beta version of the OS was already out then and Neowin did a dedicated piece on it about all the compatible devices.
A couple of days ago, the software was finally available to everyone alongside iOS 18 and watchOS 11. Apple also released a list of its tablets which are compatible with iPadOS 18. It stated:
iPadOS 18 is available for iPad Pro (M4), iPad Pro 12.9-inch (3rd generation and later), iPad Pro 11-inch (1st generation and later), iPad Air (M2), iPad Air (3rd generation and later), iPad (7th generation and later), and iPad mini (5th generation and later).
However, despite being in beta for three months, it looks like a major bug managed to slip through during testing for quality control and assurance as the update is bricking iPad Pro M4 models.
The issue was brought to attention by Apple iPad Pro M4 users who were kept holding on to dead tablets post-update even though their devices were perfectly fit and healthy before proceeding with the iPadOS 18 update. Essentially, the affected tablets do not turn on after the update.
Thankfully, Apple has pulled the update from its servers as it is no longer available for downloading. However, bear in mind that not every iPad Pro (M4) has been bricked after this implying that there is more to the story here and may explain how and why such a major fault managed to slip through without detection during testing.