Hikvision's R6 series of IP cameras raised the bar from the R0 series of entry-level devices, adding improved sensors, higher resolution and new features.
Hikvision also ramped up their support for their authorised reseller channels over the low-cost on-line sellers by adding security features in the hardware and the firmware to make it more difficult for the on-line sellers to address the Western market with China-region devices.
It took a few firmware revisions for the R6 firmware to settle down and shake the bugs out, so there was more reason than usual to consider updating.
The enhanced tamper protection and hardware signature protection just provided a challenge for those interested in circumventing it, so there was no shortage of tools and tricks to counter these efforts and assist the on-line sellers with hacked firmware.
R6 series IP camera models:
R6 series firmware - see models list IPC_R6_EN_STD_5.5.53_1807
Hikvision R6 firmware