one user of sony xperia sp repor on sony talk.sonymobile(dot)com/the result of change to 4.3, i desagree completely my phone is worse than it was bought.
but here's the report:
Memory management problem is fixed...
Led works perfect on walkman even at 100%
Smooth UI and good touch response
Volume bar issue fixed
Better and more stable wi-fi
Battery usage is like 4.1.2 (good)
Good antutu benchmark results (23500++) compared to 4.1.2 (21000+)
See this link,ure not alone: talk.sonymobile(dot)com/t5/Xperia-SP/Bugfixes-on-12-1-A-1-201-and-flickering-that-still-exists/td-p/629113
we can only hope the sony said on its website "Under Investigation
Android 4.4 (KitKat) for Sony Experia SP) briefly be with another android version and hopefully be better than this and that all errors are corrected.
Visit and stay informed---> sonymobile(dot)com/gb/software/phones/xperia-sp/#