Not much details are available concerning the exact changes and modifications that the updates come with, other than the passing mention of Android security patches, but it does come in a timely manner. Meaning, not too long after Samsung issued a promise that there will be regular (monthly if possible) security updates for its devices, especially after what happened with the Stagefright issue.
You should be able to see this update hit your device soon – if not already, but if you cannot wait and would like to perform the update manually, you can always do a check yourself by heading to Settings > About device > Software update on your handset. [Press Release]