Apple has determined that the sleep/wake button mechanism on a small percentage of iPhone 5 models may stop working or work intermittently. iPhone 5 models manufactured through March 2013 may be affected by this issue.

Apple will replace the sleep/wake button mechanism, free of charge, on iPhone 5 models that exhibit this issue and have a qualifying serial number.

In case you have problems with your iPhone 5 sleep/wake button, go to  to check if your iPhone 5 is eligible for this free repair.

Production problems can happen, and I always like the way Apple responds to it with transparency and fast solutions.