#Checking for updates
1. apt update

#If you need XEN hypervisor:
2. apt install xen-hypervisor-amd64

#Network fallback to oldschool (and also disabling ipv6):
3. apt install net-tools
4. apt install ifupdown
5. /etc/default/grub:
GRUB_CMDLINE_LINUX="ipv6.disable=1 do_not_use_netplan=true"
update-grub2

(If you need XEN hypervisor):
6. /etc/default/grub.d/xen.cfg:
GRUB_CMDLINE_XEN="dom0_mem=2G,max:2G"
update-grub2

7. rm /etc/netplan/*
8. /etc/network/interfaces (example with bridge for XEN):
auto lo
iface lo inet loopback

auto enp3s0
iface enp3s0 inet manual

auto br0
iface br0 inet dhcp
    bridge_ports enp3s0

#Time
9. Changing hwclock to localtime
/etc/default/hwclock:
HWCLOCKPARS="--localtime"

rm /etc/adjtime
hwclock --systohc --localtime --debug

timedatectl set-timezone Europe/Moscow
timedatectl set-ntp true

localectl set-locale LC_TIME="en_GB.UTF-8"

/etc/systemd/timesyncd.conf:
[Time]
NTP=2.ru.pool.ntp.org
FallbackNTP=ntp.ubuntu.com

systemctl restart systemd-timesyncd.service

reboot

# some tools for data exchange

apt install zip
apt install sshpass