Microsoft previously announced that Windows 8.1 users need to update to Windows 8.1 update by to further receive security updates. Microsoft has now extended the deadline to June 10th, so customers will continue to receive security updates even though they are in Windows 8.1.
While we believe the majority of people have received the update, we recognize that not all have. Having our customers running their devices with the latest updates is super important to us. And we’re committed to helping ensure their safety. As a result, we’ve decided to extend the requirement for our consumer customers to update their devices to the Windows 8.1 Update in order to receive security updates another 30 days to June 10th. As noted previously, consumer customers who do not update their Windows 8.1 devices to the Windows 8.1 Update by this new deadline will no longer receive updates. We’re confident that within the next month, the majority of the remaining customers who haven’t updated their devices to the Windows 8.1 Update will be able to do so.
To know about getting the Windows 8.1 Update, click here
Source: Windows team blog