Share your experience!
my phone battery is draining so fast
You can wait some more for the OS to stabilize or you can try a software repair:
http://www.sonymobile.com/gb/tools/pc-companion/
Please check out my post.
/t5/Xperia-M-M-dual/Battery-drain-after-15-4-A-1-9-update-found/m-p/788209#U788209
Let me know if it worked for you.
THanks,
Harshana