Sprint is continuing it's rollout of Android 4.4 KitKat to their devices. Today, they are rolling it out to the Sprint Galaxy Note 2 here in the US, as well as the Galaxy Mega 6.3 for those that have the international version. The Sprint Galaxy Note 2 is getting updated to software version L900VPUBNE2, which brings it to the latest version of Android. Right now the changelog isn't available but we basically know what Samsung has in store for the Galaxy Note 2. Aside from the KitKat improvements from Google, we should also see the new version of Samsung KNOX, that'd be KNOX 2.0, and a few other bug fixes and performance enhancements. We likely won't see the new version of Touchwiz on either of these devices since Samsung has never pushed the new version of their skin onto older devices before.
Now onto the Galaxy Mega 6.3. This is the GT-I9200, so if you don't have that model of the Galaxy Mega 6.3, then you aren't getting your update today. It's being updated to software version I9200XXUDNE4. Much like the Galaxy Note 2 on Sprint, there is no changelog just yet, but it's pretty safe to assume that the changelog is very similar to the Galaxy Note 2's changelog. We should start to see more countries getting their hands on KitKat for the Galaxy Mega 6.3 soon, especially those on AT&T and Sprint with those large devices. As well as the smaller Mega, the Galaxy Mega 5.8 getting it's update soon. As always we'll be sure to keep an eye out for these updates.
If you haven't received your update just yet, you can head into Settings > About Phone > System Updates > Check For Updates, and you should be able to pull down your KitKat update for your Galaxy Note 2 on Sprint or Galaxy Mega 6.3.