New firmware with the build number 10.7.A.0.228 has been certified for older Xperia Z series over PTCRB. It has been a long time since a new firmware update has certified for older Xperia Z series. This new fimware has been certified for Xperia Z, Xperia ZR and Xperia ZL. This looks like a minor firmware update as it goes from build number 10.7.A.0.222 to build number 10.7.A.0.228. We will let you know when the update starts to rollout.