I don't know this is bug or not. I have been using the old version for a long time (v3.7.2). I decided to try the new version and then buy it but I realized that the sound processor is different. Of course, this difference is in a good way, especially in cabinet simulations. I heard that the noise or low signals behave differently when I loaded my old presets. Especially the noisy gate behavior completely changed. In the old version the separation between low signal and noise was very clean. I had set the noise gate 53 on the old version V3 but in V4 is 84 but not good as before. Pass through totaly different. In the new version, these low signals are overprocessed inside the main signal and can be heard severely. In the old version the strings sound could transmit as clean as possible even when I rub my hand. It responded very well, especially at high gain settings. If you want, I can record and send audio in both versions for you to understand the situation.