On servers that have Gameshark installed and enabled, the Gameshark UI flickers for clients. For example, if there's a Pokeloot nearby, the UI will be grey and say "searching..." for a few seconds, then flash yellow for half a second, with a line drawn towards the Pokeloot, then the line and yellow flash will disappear. This was only tested on a pre-existing server that upgraded from 8.3.0 Pixelmon to 8.3.1 Pixelmon. In singleplayer it seems that the general consensus is that it works. However, someone has reported being unable to open the GUI and someone else (myself) has reported being unable to launch a single-player world with Gameshark enabled, cheats enabled, and on a creative world.