Sony Mobile stated that owners of Xperia Z1, Xperia Z1 Compact and Xperia Z Ultra devices rolling Android 4.4 KitKat that were encountering sound bugs after the Android 4.4 KitKat update, will receive an upgrade starting in April 7, next week. The upgrade will fix the strange audio functionality and quality of their devices. The availability of the upgrade will depend on the region and/or carrier.
The mentioned Xperia devices recently updated with Android 4.4.2 KitKat firmware was mostly well received. One significant bug that seemed for some users is a sound bug, and the users are not capable of hearing calls, notifications, alarms or video, the audio being delivered to the internal speaker rather than the external one.
More information regarding this subject you can find on Xperia blog.
Stay tuned for news.