Samsung released new firmwares for its 840 and 840 Pro series SSDs. The firmware with version number DXT09B0Q for the 840 and DMX06B0Q for the 840 Pro can be downloaded in both the .ZIP and .ISO format. The ISO has to be put on a CD or USB stick and can be used on all operating systems.
The zip file can be installed using Samsung Magician in Windows. Samsung writes on its website that the update brings "Improved compatibility with ultra-slim and mobile PCs."
You can download the updates from the Samsung website.