NSAppKitVersionNumber10_10 doesn't work

I am using below code to check OS X version at runtime.

if (floor(NSAppKitVersionNumber) <= NSAppKitVersionNumber10_10)
{
    /* On a 10.10.x or earlier system */
}

But this condition return false on 10.10.4 OS X. I am using Xcode 6.3.2.

According to AppKit Release Notes for OS X v10.11, It should work.

if (floor(NSAppKitVersionNumber) <= NSAppKitVersionNumber10_9) {
  /* On a 10.9.x or earlier system */
} else if (floor(NSAppKitVersionNumber) <= NSAppKitVersionNumber10_10) {
  /* On a 10.10 - 10.10.x system */
} else {
  /* 10.11 or later system */
}

via Chebli Mohamed