I’d gone up to v4.50.000, they’ve obviously found something to correct. The only issue I’ve had is being unable to view my cameras using Hik Connect via the NVR’s IP address on my network (having also upgraded all of them, mainly DS-2CD2386G2-ISU/SL to remove the two way audio issue which was successful) using an old iPad as the monitor. Added the NVR manually and no problem. I’m thinking more an iOS issue? Using Hik Connect and the IP address on iPhone 12pro and everything is perfect using either the IP address or manual addition.