Lava has rolled out updates for the Iris X1 and the Iris X5 handsets. The updates includes bug fixes, fixed restart issue faced by some users and performance improvement. It is a FOTA update, you might have already got the notification for the same.
The other way to check for software updates is to tap settings, about, software update and then hit the check for update button. For any software updates it is recommended that you use Wi-Fi for 3G networks.
Also make sure that the battery level is over 50%, preferably over 75%. It would be better if you can backup your data, though is most cases the data will be intact. However lava has specially mentioned to take the backup as they recommend doing a factory reset after the new update.