It is also not uncommon for Denon to not produce the "upper" end series with new yearly changes. IIRC the 43 series is now their top receiver or at least I remember rumblings about them doing this; that is to say dropping the 48XX and 53XX series.

Jason
M80 v2
VP160 v3
QS8 v2
PB13 Ultra
Denon 3808
Samsung 85" Q70