[Jessy1098]

I updated my Lumia to amber.. But I cannot use that feature. It hides suddenly when I open the touch option in settings.. Someone pls confirm whether this phone supports wake up feature or not.....

[cuwe]

It's not available for Lumia 620 & 520 . And that is a glitch .

[Jessy1098]

It's not available for Lumia 620 & 520 . And that is a glitch .

now I relieved... Thanks....

[Shawn Magm]

It's available for the AT&T version of the 520. It works on mine, although there are times I have to tap 3, 4 or more times in order to wake the phone.

[Lloydbm4]

It's available for the AT&T version of the 520. It works on mine, although there are times I have to tap 3, 4 or more times in order to wake the phone.

I have the AT&T version of the 520 and it does not work for me.

[Tim Zeus]

it's available on Lumia 521

[Shawn Magm]

I have the AT&T version of the 520 and it does not work for me.

Don't mean to sound condescending, but did you go to Settings - touch - Double tap to wake set to on?

[nocial]

It's not available for Lumia 620 & 520 . And that is a glitch .

available for some 520..

[Sebastianx]

it's available on Lumia 521

Nokia Lumia Amber update will bring you Double Tap to wake feature, currently it is not supported for Lumia 720, 720T, 625, 620, 521, 520 and 520T.

Source
FAQ - FAQ - What is Double Tap to wake on my Nokia Lumia phone? - Nokia