Upgrade to Lollipop stops sound notifications

[Triton3]

Hi, yesterday I upgraded from Kit Kat 4.4.4 to Lollipop 5.1 and found that the notifications for the various apps have been messed up. The LED light sometimes flashes but not always and most sound notifications don't work except one or two but even then only a small part of the notification of about 2 secconds can be heard. Fortunately the vibrations still works. 

With Kit Kat I was using Mega Sound to be able to assign different sounds to different apps and Zedge to have a bigger selection of sounds. 

So is there something that can be done to bring back the sound notifications? Or if not can one downgrade back to Kit Kat? 

[MarlonUk1]

you can try to run Xperia diagnostics and check if the hardware functions properly on safe mode.

try to perform a software repair using Xperia Companion

how about using 3rd part apps just like you did on kitkat

[Triton3]

Thanks Nolram, I will try what you said. All apps including third party ones carried over to Lollipop.