I have only had the 4.950 update out on the water once so far. My first impression is that the 2D, DI and SI picture is softer or blurry. I am also not getting any shadows when I go by pilings or vertical structure. I did not notice a big improvement of the digital shallow water depth readings. I am using the unit in saltwater and have the water type set to 'Salt Water (shallow). I am thinking of going back to 4.750.
I have made several changes to my installation and I am not sure if that may have affected the image quality. I relocated the HDSI transducer to the transom set back with a 'Transducer Shield' bracket and added a dual beam transducer for high speed depth readings. I appear to be getting air bubbles on the transducer on the SI screen. The manufacturer is sending me new spacers to change the angle and depth of the transducer. Hopefully this will help.
The update did fix some problems I was having with the ContourXD map not rendering the coast line. I did not check to see if there were any improvements with Platinum 3D on the birdseye view screens.
It would be great if Humminbird would provide a list of fixes and known issues so the users would not spend so much time trying to fix something with settings that is really a software problem. I think this would improve feedback from the users and do a lot to enhance customer service credibility.