Special thanks to Thomasfan89 for helping me out on this.
This affects the HD 400 and 420 series for sure, but I'm not sure on the others. You may find that when you try to view video from the year 2020, there appears to be none. Don't panic...it's most likely your playback software, not something with the camera system.
Go to http://www.radioeng.info/index.html and download the software provided there. I recommend removing all traces of the old software and it's subfiles first, just to prevent any issues.
It's also a good time to do firmware updates to the DVRs if you haven't already!
Had an issue on a bus earlier this week and that "OH CRAP" moment when you think the camera system didn't work. Get newest software, and there was the video!