It looks like owners of the Xperia Z2 are starting to notice a minor firmware update being pushed out to them from Sony. The firmware version number is 17.1.2.A.0.314. Though the update is rolling out now, it doesn't bring the latest Android 4.4.4 to the table as it keeps the Xperia Z2 at Android 4.4.2.
At this time, there is no change log to report on, so we're guessing that Sony may be ironing out some performance issues and bug fixes.
Have you gotten this latest firmware build? Are you noticing any big changes or improvements?