While many smartphones running on Android are yet to receive the April security patch from Google, the Samsung Galaxy S7 Edge has already started receiving the patch for May well ahead of time in South Korea. Generally, Samsung devices in South Korea receive updates for their devices much before other regions given it is home to the parent company.
The update weighs close to 36.65MB in size with build number MMB29K.G935SKSU1APAD and as shown in the image below. It provides the Android security patch level for 1 May 2016. The update was spotted on an SK Telecom variant of the Galaxy S7 Edge with model number SM-G935S. It seems likely that the other two major carriers in South Korea like KT and LG U+ may also start receiving the patch soon.
Traditionally, Google always seeds the Android security patch to its home-bred brand Nexus after which a host of other flagships get the updates. In this case, the Galaxy S7 Edge has outdone the Nexus to be the first device to receive this update. This means Google too is ready with the May 2016 Android security patch and other devices should also expect it soon.
As for South Korea, it seems more than Samsung, it is the carriers in the nation that have struck a better deal with Google to ensure speedy roll outs for Android updates. As for Galaxy S7 Edge and Galaxy S7 owners in other regions, you may have to wait a short while before the patches hit your device.