The next version of KitKat, Android 4.4.3 is quickly approaching it'd seem, as we've seen it pop up all over the internet and most recently we've been seeing Samsung work with the new software. We're sure that this latest point release is to come with lots of bugfixes and maintenance updates, rather than new features, but keeping a software build up-to-date and secure is always a good idea, especially given how long recent versions of Android have stayed "current" and supported by Google. We've seen before that Samsung is working with this latest code from Google and now, SamMobile have gotten their hands on internal documents suggesting that Samsung is close to releasing the new version of Android onto devices.
An internal document from Samsung, dated the 21st of May, details that a KitKat build dubbed 'KTU70' is being tested on the Galaxy S4 LTE-A model as well as the Galaxy S5. According to the document, these updates are currently 'integrating' which seems to be the merging of sorts of TouchWiz and the latest Android code. As this is such a minor point release, this process shouldn't take all that long.
As for Android 4.4.2, it looks like Samsung is getting ready to roll out KitKat to even more of their devices, as another internal document - this one dated 21st of May as well - gives us an update on older devices and the KitKat update. The Galaxy Mega 5.8 and 6.3 are listed as being in 'Final Testing' along with the Galaxy Grand 2. The Galaxy Note 3 Neo and Galaxy S4 Mini LTE (not to be confused with the non-LTE version which will see the update in June) are pending with ETAs of May and June, respectively. As for the Galaxy S3, it's only the LTE version powered by a Snapdragon CPU and 2GB of RAM that is to get the update as Samsung has already said that the i9300 version cannot run Android 4.4.2 with all of their features on top of it.