802.1q vlan naming in Debian 10

Upgrading router and facing problem VLAN interfaces does not go up (error "Unknown interface" if perform 'ifup vlanxxx') if vlans are defined in following manner:

auto vlanxxx
iface vlanxxx inet static
vlan-raw-device eno1
address 192.168.0.1
netmask 255.255.255.0

but it does load if I change VLAN names definition in following manner:

auto eno1.xxx
iface eno1.xxx inet static
address 192.168.0.1
netmask 255.255.255.0

in https://wiki.debian.org/NetworkConfiguration#Manual_config both VLAN naming convention are described, what am I doing wrong?

You are most certainly lacking the add-on package vlan:

ifupdown integration for vlan configuration

This package contains integration scripts for configuring vlan interfaces via ifupdown (/etc/network/interfaces). For further details see vlan-interfaces(5) man page in this package.

It also suggests that its VLAN support is limited and one should use one's own iproute2 commands anyway.

Without this add-on package, vlan-raw-device is not a valid command, while interfaces(5) still documents direct support for the interface.VID scheme.

Historically the main use of this package was to provide the vconfig command: it's still provided, but this command has been entirely replaced by ip link commands in the add-on scripts. Now, its main use is to provide the additional VLAN-related commands for ifupdown. About the same goes with the package bridge-utils: not really for its obsolete (but strangely still widely in use) brctl command but for its ifupdown configuration add-on, which still does rely on brctl though.

There is also a complete reimplementation available with the ifupdown2 package which doesn't rely on any obsolete command nor add-on and is mostly (but not completely) compatible, and there might possibly be in the future a new Debian implementation called ifupdown-ng.