Where i can get PVR SDK 3.1?

PowerVR Insider
1

I need to get pvr sdk 3.1.
Latest PVRTextTool is simply unable to generate pvrtc4 image quality comparable with the one in sdk 3.1.
Compare:
https://www.dropbox.com/s/7iq4sa4sms487ri/Screenshot%202015-06-13%2002.59.02.png?dl=0

2

Would it be possible for you to attach the image files, including the original source file?

Could you also grab the build the number for PVRTexTool. You can do this either by running the command line tool without parameters, or from PVRTexToolGUI by selecting Help -> Feedback.