Android 4.4.4 to Android 4.3 Jelly Bean

[squrrel]

hello. You can switch from Android 4.4.4 to Android 4.3 Jelly Bean via PC Companion?

[Uliwooly]

no, you need to use flashtool to do so

[Uliwooly]

You can check the steps here

http://talk.sonymobile.com/t5/Xperia-Z2/How-to-manually-update-downgrade-root-2014-Xperias/td-p/5934...

just download the FTF file from the XDA Forum 

[Uliwooly]

The other alternative will be to contact your local Xperia care and request to downgrade your phone 

http://support.sonymobile.com/global-en/contactUs/

[squrrel]

and warranty service be? phone got 14 days

[Thommo]

I'd say unofficially yes as long as the firmware you use is the correct one for your country and for the phone via it's country code known as a SI number