not available to msia yet though

kitkat indeed is quite terrible...battery life was poor and wechat malfunctioned instantly with the stuttering notification tones...had no choice but to downgrade it to 4.3 ...will wait till sony fixed all these issues

http://forum.xda-developers.com/showthread.php?t=2469191

becareful on what you're doing .. hahah i'm not responsible if you brick ur phone..

stuttering notifications didn't kena? like the tone jam a while den only play...like file corrupted...den we chat always see the chat box become black sometimes..words also black the background also black..den the person ur chatting with info also hilang...and battery i noticed drain much faster leh after update...

have to revert lower..681 is already kit kat (the problematic firmware before 757)

not really bro, i just got my phone 2 weeks ago and realized the best was during JB...after it went to kit kat it was horrible.. when i forced downgrade to JB, the phone became unstable..suddenly auto restart..suddenly sleep of death... forced me to go up to kitkat again..sigh

perhaps can login with a new account instead? do check your date and time of your phone is correct as well..

Recently took it to phuket with me as my daily camera... seriously, takes good pics BUT, i think i spent more time letting it cool down than snapping pics, it overheats too damn fast.. =(

I just had the sudden hang and screen fade issue.. Had to use the pwr + volume up key to force shut down. Seems like have to wait a while before can power on to restore to normal state as immediately powering on will not turn on the screen even after a force shut down. Seriously the new firmware kinda sucks