A firmware has been released for the NVR8-7400 and the NHD-818 and 819 cameras.
This update is primarily to address reliability with regards to the attachment of images to email notifications.
Updating the firmware on the NVR is covered in this PDF. Instructions for the cameras are below. The firmware files are unzipped and ready to be copied straight to a USB stick.
Apply the firmware to the cameras:
Insert the USB memory stick into one of the recorder's USB ports.
Open the menu on the recorder and proceed to System > Maintenance.
In the Maintenance tab, choose the Upgrade IPC from USB button.
On the preparation screen, please click on Browse for each camera and select the new firmware file for each channel from the USB stick.
Once all cameras have firmware files specified, click on the Upgrade button.
The progress indicators will fill and advise when all updates are complete.
Repeat this step with the old firmware file for any cameras that failed, in case some of your cameras are the first hardware revision.