iVMS NVR - only recording rolling seven days - WHY?

I'm trying to get my NVR to record more than seven days of content. It seems to only allow me access to the rolling last seven days. I have 8 TBs of storage on the NVR (2 x 4 TB drives). Is seven days a limitation or have I missed a setting somewhere?

Specs:

iVMS-4200 V2.6.2.6 build20170719

Device type: SC-318P6-16

Firmware: V3.4.92 build 170224

Any help much appreciated.