Share your experience!
I have purchased C4 dual last week, previously I was using T2ultra dual, which is a very nice phone. As per configuration C4 is almost double to T2 ultra, but unfortunately I still find T2 ultra is much better (except screen resolution).
1) I am not able to play videos on C4, phone is restarting again and again.
2) My company IT people are not able to configure my WIFI.
3) OS is still 5.0, however in T@ ultra it is 5.0.2.
I am very disappointed. 
5.0.2 is latest for both devices. Go to settings-about phone and check.
About restarting,does the same occur without a SIM?
And related to wifi,what are they trying to configure on your C4?
Hi @doct4u
Related to WIFI configuration you can check this link:
http://support.sonymobile.com/global-en/xperiac4/faq/I-cannot-connect-to-my-home-Wi-Fi-network/
Hope can be useful
Best Regards