Are you sure both are N2 hardware version? Does the one with DVB-T2 play video encoded in h265? There are many versions of these decoders and some also differ in processor and other electronics. The manufacturer does not know why he made purges on his technical support page, but if you believe the specification that has been preserved on the Internet, the N2 hardware version only supports DVB-T and Mpeg4. The N5 hardware version has newer DVB-T2 heads, but the processor cannot handle the h265 codec. There is also the latest OPTICUM T90 HEVC with dvb-t2. It has a completely different processor that supports the h265 codec.
