After each upgrade I look through all settings to see what has changed. Hikvision maybe trying to pull a fast one on users with "GREY MARKET" equipment. I upgraded my eBay bought Hikvision NVR DS-7608NI-I2/8P to the latest firmware version V4.1.61build180818 and noticed a sneaky setting turned on. They enable auto firmware update, i know for a lot of users who have hacked versions if this happened would most likely brick their NVR. If you have upgraded but have not checked through the settings, do so at your earliest convenience.