Apple says that the rear iSight camera in "a small percentage" of iPhone 6 Plus smartphones has a component that may fail causing your photos to look blurry. If your iPhone 6 Plus is producing blurry photos and falls into the eligible serial number range, Apple will replace your device's iSight camera, free of charge.
The affected units fall into a limited serial number range and were sold primarily between September 2014 and January 2015, says Apple. You can head over to the iPhone 6 Plus iSight Camera Replacement Program page to see if your unit is eligible for camera replacement by entering the serial number of your iPhone 6 Plus (Review | Pictures).
Finding the serial number of your iPhone 6 Plus is easy. Tap Settings > General > About to see your device's serial number. You can tap and hold on the number to copy it to the clipboard and paste it in the box provided on the replacement program page. If your device is eligible for replacement, you can head over to the nearest Apple authorised service provider for help.
Apple notes that the company may restrict or limit repair to the original country of purchase. Which means if you bought your iPhone 6 Plus in the US, you may not be able to get its iSight camera replaced in India, even if it's found to be faulty. The company adds that the program doesn't extend the standard warranty coverage of the iPhone 6 Plus. Finally, Apple says the program covers affected iPhone 6 Plus iSight cameras for 3 years after the first retail sale of the unit.
Don't forget to backup your iPhone 6 Plus before giving it in for repairs.