European Galaxy S5 users are now getting new updates. It looks like it is a major performance improvement upgrade taking the size of the software (194 MB).
As most of the Samsung Galaxy S5 customers are waiting for Android 4.4.3 or 4.4.4, it is not known why Samsung just pushes a performance improvement fix not a new Android cookie.
The update with build number XXU1ANG2 is now rolling out over the air and most of the Galaxy S5 users will get notifications sooner or later. If you want to check manually you can always try with Settings » About phone » Software updates menu.