It's not a model we have ever sold as I believe from looking at Hikvision's website it was a model only available in Europe -
DS-2CV2Q21FD-IW/(16G-T/32G-T/64G-T) 2.0 MP Network PT Camera-Hikvision Europe
After some searching, the only reference to these models that I can see is this section at the download portal -
DOWNLOAD EU PORTAL
There is no mention of a v5.5.93 firmware for the 2Q01/2Q21 cameras, I don't think this firmware is available for these cameras.