During the Galaxy S4 event, Samsung confirmed that many of Galaxy S4 features will be available via an update to Galaxy S III. Before the official release, SamMobile somehow managed to get their hands on an upcoming software update, revealing what we can expect from it.
First of all, the usual Android 4.2 features will be available, including expanded notifications, lock screen widgets and Daydream support. The next major update includes a number of unique TouchWiz toggles in the settings screen, the new driving mode and S Voice improvements.
If you are brave enough, the update is available for download and installation details are available at the source link. If not, you will have to wait until June, when Samsung will allegedly release the update.