apt-get update
apt-get dist-upgrade
edit /etc/apt/sources.list and add devuan's repos
root@debian:~# apt-get update --allow-insecure-repositories
root@debian:~# apt-get install devuan-keyring --allow-unauthenticated
root@debian:~# apt-get update
apt-get install sysvinit #may not be required
reboot #may not be required
sudo apt-get dist-upgrade #says it will delete running kernel. allow it to (I think it's "no" here, read the warning carefully)
install the kernel again. note that you can't
install linux-image-amd64, you must install the current release.
e.g. apt-get install linux-image-4.19.0-13-amd64. Whatever is most current.
make sure boot has an initramfs and kernel.
What this does is remove the debian kernel, and install the devuan kernel
sudo apt-get autoclean
sudo apt-get remove systemd libsoup2.4-1-  #this will ignore the dependency on libsoup, and allow removing systemd
it will error out. that's ok,
sudo apt-get install sysvinit-core
sudo apt-get install eudev #IMPORTANT. We must download this before rebooting. It will fail, but that is ok.
now, before you reboot make sure /etc/inittab has something in place.
It does for me, so devuan installed it this time.
now: reboot
in my vps i was locked out, because they have some strange ifup settings.
from emergency console: apt-get install eudev
after this, reboot once more to get eudev running.
the dhcp may timeout. just wait a moment.
now NICs are visible, and you should be in devuan. At least I was with my VPS.
Tested with Debian 10. 01/10/2021.

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).
source /etc/network/interfaces.d/*
# The loopback network interface
auto lo
iface lo inet loopback
auto enp
iface enp inet static
        address <WANIP>
        netmask 255.255.255.255
        broadcast +
        up ip -f inet route add 169.254.0.1 dev enp
auto enp:1
iface enp:1 inet static
        address <SOMELANIP>
        netmask 255.0.0.0
        broadcast +

Removing linux-image-amd64 (4.19+105+deb10u8) ...
Removing linux-image-4.19.0-13-amd64 (4.19.160-2) ...
E: Aborting removal of the running kernel
dpkg: error processing package linux-image-4.19.0-13-amd64 (--remove):
 installed linux-image-4.19.0-13-amd64 package pre-removal script subprocess returned error exit status 1
Removing bluetooth (5.50-1.2~deb10u1) ...
Removing bluez (5.50-1.2~deb10u1) ...
dpkg: initramfs-tools-core: dependency problems, but removing anyway as you requested:
 initramfs-tools depends on initramfs-tools-core (= 0.133+deb10u1).

Removing initramfs-tools-core (0.133+deb10u1) ...
Removing udev (241-7~deb10u5) ...
dpkg: initramfs-tools: dependency problems, but removing anyway as you requested:
 linux-image-4.19.0-13-amd64 depends on initramfs-tools (>= 0.120+deb8u2) | linux-initramfs-tool; however:
  Package initramfs-tools is to be removed.

  Package linux-initramfs-tool is not installed.
  Package initramfs-tools which provides linux-initramfs-tool is to be removed.
 linux-image-4.19.0-13-amd64 depends on initramfs-tools (>= 0.120+deb8u2) | linux-initramfs-tool; however:
  Package initramfs-tools is to be removed.
  Package linux-initramfs-tool is not installed.
  Package initramfs-tools which provides linux-initramfs-tool is to be removed.

Removing initramfs-tools (0.133+deb10u1) ...
Errors were encountered while processing:
 linux-image-4.19.0-13-amd64
E: Sub-process /usr/bin/dpkg returned an error code (1)
root@vps:/#

root@vps:~# apt-get install eudev
Reading package lists... Done
Building dependency tree
Reading state information... Done
You might want to run 'apt --fix-broken install' to correct these.
The following packages have unmet dependencies:
 eudev : Depends: libeudev1 (= 3.2.7-6) but it is not going to be installed
         Breaks: systemd (> 220) but 241-7~deb10u5 is to be installed
 linux-image-4.19.0-13-amd64 : Depends: initramfs-tools (>= 0.120+deb8u2) but it is not going to be installed or
                                        linux-initramfs-tool
E: Unmet dependencies. Try 'apt --fix-broken install' with no packages (or specify a solution).
root@vps:~# apt-get purge systemd libnss-systemd
Reading package lists... Done
Building dependency tree
Reading state information... Done
You might want to run 'apt --fix-broken install' to correct these.
The following packages have unmet dependencies:
 dbus-user-session : Depends: systemd but it is not going to be installed
 libpam-systemd : Depends: systemd (= 241-7~deb10u5) but it is not going to be installed
 linux-image-4.19.0-13-amd64 : Depends: initramfs-tools (>= 0.120+deb8u2) but it is not going to be installed or
                                        linux-initramfs-tool
 systemd-sysv : PreDepends: systemd but it is not going to be installed
                Recommends: libnss-systemd but it is not going to be installed
E: Unmet dependencies. Try 'apt --fix-broken install' with no packages (or specify a solution).
root@vps:~# apt-get install -f
Reading package lists... Done
Building dependency tree
Reading state information... Done
Correcting dependencies... failed.
The following packages have unmet dependencies:
 linux-image-4.19.0-13-amd64 : Depends: initramfs-tools (>= 0.120+deb8u2) but it is not installed or
                                        linux-initramfs-tool
E: Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.
E: Unable to correct dependencies
root@vps:~#

root@vps:~# sudo apt-get install libeudev1
Reading package lists... Done
Building dependency tree
Reading state information... Done
You might want to run 'apt --fix-broken install' to correct these.
The following packages have unmet dependencies:
 libeudev1 : Conflicts: libudev1 (< 1:3.2.7-6)
 linux-image-4.19.0-13-amd64 : Depends: initramfs-tools (>= 0.120+deb8u2) but it is not going to be installed or
                                        linux-initramfs-tool
E: Unmet dependencies. Try 'apt --fix-broken install' with no packages (or specify a solution).
root@vps:~# sudo apt-get install initramfs-tools
Reading package lists... Done
Building dependency tree
Reading state information... Done
You might want to run 'apt --fix-broken install' to correct these.
The following packages have unmet dependencies:
 initramfs-tools : Depends: initramfs-tools-core (= 0.133+deb10u1) but it is not going to be installed
E: Unmet dependencies. Try 'apt --fix-broken install' with no packages (or specify a solution).
root@vps:~# sudo apt-get install initramfs-tools initramfs-tools-core
Reading package lists... Done
Building dependency tree
Reading state information... Done
You might want to run 'apt --fix-broken install' to correct these.
The following packages have unmet dependencies:
 initramfs-tools-core : Depends: udev
                        Recommends: pigz but it is not going to be installed
E: Unmet dependencies. Try 'apt --fix-broken install' with no packages (or specify a solution).
root@vps:~#

root@vps:~# apt-get upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
The following package was automatically installed and is no longer required:
  aspell-eu-es
Use 'apt autoremove' to remove it.
The following packages have been kept back:
  libcolord2 libudev1 udev util-linux
The following packages will be upgraded:
  base-files bsdutils ca-certificates distro-info-data fdisk libblkid1 libfdisk1 libmount1 libpcsclite1 libprocps7 libsmartcols1 libuuid1
  mount procps python3-reportbug reportbug rsyslog sysvinit-utils task-amharic task-arabic task-asturian task-basque task-belarusian
  task-bengali task-bosnian task-brazilian-portuguese task-bulgarian task-catalan task-chinese-s task-chinese-t task-croatian
  task-cyrillic task-czech task-danish task-dutch task-english task-esperanto task-estonian task-finnish task-french task-galician
  task-german task-greek task-gujarati task-hebrew task-hindi task-hungarian task-icelandic task-irish task-italian task-japanese
  task-kazakh task-khmer task-korean task-kurdish task-laptop task-latvian task-lithuanian task-macedonian task-malayalam task-marathi
  task-northern-sami task-norwegian task-persian task-polish task-portuguese task-punjabi task-romanian task-russian task-serbian
  task-slovak task-slovenian task-spanish task-swedish task-tagalog task-tamil task-telugu task-thai task-turkish task-ukrainian
  task-welsh tasksel tasksel-data tzdata util-linux-locales uuid-runtime
86 upgraded, 0 newly installed, 0 to remove and 4 not upgraded.
Need to get 4,510 kB of archives.
After this operation, 644 kB of additional disk space will be used.
Do you want to continue? [Y/n]

etting up task-khmer (3.54+devuan3) ...
Setting up task-gujarati (3.54+devuan3) ...
Setting up task-northern-sami (3.54+devuan3) ...
Setting up task-belarusian (3.54+devuan3) ...
Setting up task-english (3.54+devuan3) ...
Processing triggers for systemd (241-7~deb10u5) ...
Processing triggers for man-db (2.8.5-2) ...
Processing triggers for libc-bin (2.28-10) ...
Processing triggers for ca-certificates (20200601~deb10u1) ...
Updating certificates in /etc/ssl/certs...
0 added, 0 removed; done.
Running hooks in /etc/ca-certificates/update.d...
done.

root@vps:~# apt-get install eudev
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 dconf-gsettings-backend : Depends: dconf-service (>= 0.30.1-2) but it is not going to be installed
                           Depends: dconf-service (< 0.30.1-2.1~) but it is not going to be installed
 libsoup2.4-1 : Depends: glib-networking (>= 2.32.0) but it is not going to be installed
E: Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.
root@vps:~#

# /etc/inittab: init(8) configuration.

# The default runlevel.
id:2:initdefault:

# Boot-time system configuration/initialization script.
# This is run first except when booting in emergency (-b) mode.
si::sysinit:/etc/init.d/rcS

# What to do in single-user mode.
~~:S:wait:/sbin/sulogin

# /etc/init.d executes the S and K scripts upon change
# of runlevel.
#
# Runlevel 0 is halt.
# Runlevel 1 is single-user.
# Runlevels 2-5 are multi-user.
# Runlevel 6 is reboot.

l0:0:wait:/etc/init.d/rc 0
l1:1:wait:/etc/init.d/rc 1
l2:2:wait:/etc/init.d/rc 2
l3:3:wait:/etc/init.d/rc 3
l4:4:wait:/etc/init.d/rc 4
l5:5:wait:/etc/init.d/rc 5
l6:6:wait:/etc/init.d/rc 6
# Normally not reached, but fallthrough in case of emergency.
z6:6:respawn:/sbin/sulogin

# What to do when CTRL-ALT-DEL is pressed.
ca:12345:ctrlaltdel:/sbin/shutdown -t1 -a -r now

# Action on special keypress (ALT-UpArrow).
#kb::kbrequest:/bin/echo "Keyboard Request--edit /etc/inittab to let this work."

# What to do when the power fails/returns.
pf::powerwait:/etc/init.d/powerfail start
pn::powerfailnow:/etc/init.d/powerfail now
po::powerokwait:/etc/init.d/powerfail stop

# /sbin/getty invocations for the runlevels.
#
# The "id" field MUST be the same as the last
# characters of the device (after "tty").
#
# Format:
#  <id>:<runlevels>:<action>:<process>
#
# Note that on most Debian systems tty7 is used by the X Window System,
# so if you want to add more getty's go ahead but skip tty7 if you run X.
#
1:2345:respawn:/sbin/getty 38400 tty1
2:23:respawn:/sbin/getty 38400 tty2
3:23:respawn:/sbin/getty 38400 tty3
4:23:respawn:/sbin/getty 38400 tty4
5:23:respawn:/sbin/getty 38400 tty5
6:23:respawn:/sbin/getty 38400 tty6

# Example how to put a getty on a serial line (for a terminal)
#
#T0:23:respawn:/sbin/getty -L ttyS0 9600 vt100
#T1:23:respawn:/sbin/getty -L ttyS1 9600 vt100

# Example how to put a getty on a modem line.
#
#T3:23:respawn:/sbin/mgetty -x0 -s 57600 ttyS3

Accept this solution? [Y/n/q/?] n
open: 2936; closed: 7563; defer: 329; conflict: 279                            .The following actions will resolve these dependencies:

      Remove the following packages:                                      
1)      libpolkit-backend-1-0 [0.105-25+devuan8 (now, testing)]           
2)      libpolkit-backend-consolekit-1-0 [0.105-25+devuan8 (now, testing)]
3)      libsystemd0 [241-7~deb10u2 (now, testing)]                        
4)      mate-applet-brisk-menu [0.5.0-9 (now, testing)]                   
5)      mate-applets [1.20.3-2 (now, testing)]                            
6)      mate-control-center [1.20.4-2 (now, testing)]                     
7)      mate-desktop-environment [1.20.0+5 (now, testing)]                
8)      mate-desktop-environment-core [1.20.0+5 (now, testing)]           
9)      mate-panel [1.20.5-1 (now, testing)]                              
10)     mate-polkit [1.20.2-1 (now, testing)]                             
11)     mate-power-manager [1.20.3-2 (now, testing)]                      
12)     mate-settings-daemon [1.20.4-1 (now, testing)]                    
13)     policykit-1 [0.105-25+devuan8 (now, testing)]                     
14)     qupzilla [1.8.9~dfsg1-3.1 (now)]                                  
15)     rtkit [0.11-6 (now, testing)]                                     
16)     synaptic [0.84.6 (now, testing)]                                  
17)     task-mate-desktop [3.54+devuan3 (now, testing)]                   

      Install the following packages:                                     
18)     exo-utils [0.12.4-1 (testing)]                                    
19)     gtk2-engines-xfce [3.2.0-4 (testing)]                             
20)     i3lock [2.11.1-1 (testing)]                                       
21)     libev4 [1:4.25-1 (testing)]                                       
22)     libexo-1-0 [0.12.4-1 (testing)]                                   
23)     libexo-2-0 [0.12.4-1 (testing)]                                   
24)     libexo-common [0.12.4-1 (testing)]                                
25)     libexo-helpers [0.12.4-1 (testing)]                               
26)     libgarcon-1-0 [0.6.2-1 (testing)]                                 
27)     libgarcon-common [0.6.2-1 (testing)]                              
28)     libkeybinder-3.0-0 [0.3.2-1 (testing)]                            
29)     libnotify-bin [0.7.7-4 (testing)]                                 
30)     libreoffice-gtk2 [1:6.1.5-3+deb10u5 (testing)]                    
31)     libtagc0 [1.11.1+dfsg.1-0.3 (testing)]                            
32)     libthunarx-3-0 [1.8.4-1 (testing)]                                
33)     libtumbler-1-0 [0.2.3-1 (testing)]                                
34)     libwnck-common [2.30.7-6 (testing)]                               
35)     libwnck22 [2.30.7-6 (testing)]                                    
36)     libxcb-xrm0 [1.0-3 (testing)]                                     
37)     libxfce4panel-2.0-4 [4.12.2-1 (testing)]                          
38)     libxfce4ui-1-0 [4.12.1-3 (testing)]                               
39)     libxfce4ui-2-0 [4.12.1-3 (testing)]                               
40)     libxfce4ui-common [4.12.1-3 (testing)]                            
41)     libxfce4ui-utils [4.12.1-3 (testing)]                             
42)     libxfce4util-common [4.12.1-3 (testing)]                          
43)     libxfce4util7 [4.12.1-3 (testing)]                                
44)     libxfconf-0-2 [4.12.1-1 (testing)]                                
45)     mousepad [0.4.1-2 (testing)]                                      
46)     parole [1.0.1-1 (testing)]                                        
47)     pavucontrol [3.0-4 (testing)]                                     
48)     tango-icon-theme [0.8.90-7 (testing)]                             
49)     task-xfce-desktop [3.54+devuan3 (testing)]                        
50)     thunar [1.8.4-1 (testing)]                                        
51)     thunar-data [1.8.4-1 (testing)]                                   
52)     thunar-volman [0.9.1-1 (testing)]                                 
53)     tumbler [0.2.3-1 (testing)]                                       
54)     tumbler-common [0.2.3-1 (testing)]                                
55)     xfce4 [4.12.5 (testing)]                                          
56)     xfce4-appfinder [4.12.0-2 (testing)]                              
57)     xfce4-notifyd [0.4.3-1 (testing)]                                 
58)     xfce4-panel [4.12.2-1 (testing)]                                  
59)     xfce4-power-manager [1.6.1-1 (testing)]                           
60)     xfce4-power-manager-data [1.6.1-1 (testing)]                      
61)     xfce4-power-manager-plugins [1.6.1-1 (testing)]                   
62)     xfce4-pulseaudio-plugin [0.4.1-1 (testing)]                       
63)     xfce4-session [4.12.1-6+devuan2 (testing)]                        
64)     xfce4-settings [4.12.4-1 (testing)]                               
65)     xfce4-terminal [0.8.7.4-2 (testing)]                              
66)     xfconf [4.12.1-1 (testing)]                                       
67)     xfdesktop4 [4.12.4-2 (testing)]                                   
68)     xfdesktop4-data [4.12.4-2 (testing)]                              
69)     xfwm4 [4.12.5-1 (testing)]                                        

      Leave the following dependencies unresolved:                        
70)     elogind recommends policykit-1                                    
71)     libxfce4util7 recommends libxfce4util-bin                         
72)     mate-applets recommends mate-polkit                               
73)     mate-screensaver recommends mate-power-manager                    
74)     mate-session-manager recommends mate-panel                        
75)     mate-session-manager recommends mate-polkit                       
76)     mate-session-manager recommends mate-settings-daemon              
77)     pulseaudio recommends rtkit                                       
78)     task-mate-desktop recommends synaptic                             
79)     task-xfce-desktop recommends xfce4-goodies                        
80)     task-xfce-desktop recommends xsane                                
81)     task-xfce-desktop recommends quodlibet                            
82)     task-xfce-desktop recommends synaptic                             
83)     task-xfce-desktop recommends system-config-printer                
84)     thunar recommends policykit-1-gnome | polkit-1-auth-agent         
85)     udisks2 recommends policykit-1                                    
86)     upower recommends policykit-1

Accept this solution? [Y/n/q/?]

# aptitude install falkon
The following NEW packages will be installed:
  elogind{a} falkon geoclue-2.0{a} kwayland-data{a} kwayland-integration{a} 
  liba52-0.7.4{a} libaribb24-0{a} libbasicusageenvironment1{a} 
  libdbusmenu-qt5-2{a} libdouble-conversion1{a} libdvbpsi10{a} 
  libebml4v5{a} libelogind0{ab} libfam0{a} libgles2{a} libgroupsock8{a} 
  libixml10{a} libjim0.77{a} libkf5archive5{a} libkf5auth-data{a} 
  libkf5auth5{a} libkf5codecs-data{a} libkf5codecs5{a} libkf5config-bin{a} 
  libkf5config-data{a} libkf5configcore5{a} libkf5configgui5{a} 
  libkf5configwidgets-data{a} libkf5configwidgets5{a} 
  libkf5coreaddons-data{a} libkf5coreaddons5{a} libkf5crash5{a} 
  libkf5dbusaddons-bin{a} libkf5dbusaddons-data{a} libkf5dbusaddons5{a} 
  libkf5guiaddons5{a} libkf5i18n-data{a} libkf5i18n5{a} 
  libkf5iconthemes-bin{a} libkf5iconthemes-data{a} libkf5iconthemes5{a} 
  libkf5idletime5{a} libkf5itemviews-data{a} libkf5itemviews5{a} 
  libkf5notifications-data{a} libkf5notifications5{a} libkf5service-bin{a} 
  libkf5service-data{a} libkf5service5{a} libkf5wallet-bin{a} 
  libkf5wallet-data{a} libkf5wallet5{a} libkf5waylandclient5{a} 
  libkf5widgetsaddons-data{a} libkf5widgetsaddons5{a} 
  libkf5windowsystem-data{a} libkf5windowsystem5{a} libkwalletbackend5-5{a} 
  liblivemedia64{a} liblua5.2-0{a} libmad0{a} libmatroska6v5{a} 
  libmbim-glib4{a} libmbim-proxy{a} libmicrodns0{a} libminizip1{a} 
  libmm-glib0{a} libmpeg2-4{a} libopenmpt-modplug1{a} libpam-elogind{a} 
  libpcre2-16-0{a} libphonon4qt5-4{a} libplacebo7{a} libpolkit-qt5-1-1{a} 
  libprotobuf-lite17{a} libproxy-tools{a} libqmi-glib5{a} libqmi-proxy{a} 
  libqt5core5a{a} libqt5dbus5{a} libqt5gui5{a} libqt5network5{a} 
  libqt5positioning5{a} libqt5printsupport5{a} libqt5qml5{a} 
  libqt5quick5{a} libqt5quickwidgets5{a} libqt5sql5{a} libqt5sql5-sqlite{a} 
  libqt5svg5{a} libqt5texttospeech5{a} libqt5waylandclient5{a} 
  libqt5waylandcompositor5{a} libqt5webchannel5{a} libqt5webengine-data{a} 
  libqt5webenginecore5{a} libqt5webenginewidgets5{a} libqt5widgets5{a} 
  libqt5x11extras5{a} libqt5xml5{a} libre2-5{a} libresid-builder0c2a{a} 
  libsdl-image1.2{a} libsidplay2{a} libspatialaudio0{a} libupnp13{a} 
  libusageenvironment3{a} libva-wayland2{a} libvlc-bin{a} libvlc5{a} 
  libvlccore9{a} libxcb-icccm4{a} libxcb-image0{a} libxcb-keysyms1{a} 
  libxcb-randr0{a} libxcb-render-util0{a} libxcb-xinerama0{a} 
  libxcb-xkb1{a} libxcb-xv0{a} libxkbcommon-x11-0{a} modemmanager{a} 
  phonon4qt5{a} phonon4qt5-backend-vlc{a} qt5-gtk-platformtheme{a} 
  qttranslations5-l10n{a} qtwayland5{a} usb-modeswitch{a} 
  usb-modeswitch-data{a} vlc-data{a} vlc-plugin-base{a} 
  vlc-plugin-video-output{a} 
0 packages upgraded, 131 newly installed, 0 to remove and 0 not upgraded.
Need to get 51.8 MB/68.9 MB of archives. After unpacking 279 MB will be used.
The following packages have unmet dependencies:
 libpolkit-backend-consolekit-1-0 : Conflicts: elogind but 241.4-2 is to be installed
                                    Conflicts: libpam-elogind but 241.4-2 is to be installed
 libelogind0 : Conflicts: libsystemd0 but 241-7~deb10u2 is installed
The following actions will resolve these dependencies:

     Remove the following packages:                                      
1)     consolekit [1.2.1-8 (now, testing)]                               
2)     libpolkit-backend-consolekit-1-0 [0.105-25+devuan8 (now, testing)]
3)     libpolkit-gobject-consolekit-1-0 [0.105-25+devuan8 (now, testing)]
4)     libsystemd0 [241-7~deb10u2 (now, testing)]                        

     Install the following packages:                                     
5)     libpolkit-backend-elogind-1-0 [0.105-25+devuan8 (testing)]        
6)     libpolkit-gobject-elogind-1-0 [0.105-25+devuan8 (testing)]        

Accept this solution? [Y/n/q/?]

deb [arch=amd64] https://download.docker.com/linux/debian stretch stable

 sudo add-apt-repository \
   "deb [arch=amd64] https://download.docker.com/linux/debian \
   $(lsb_release -cs) \
   stable"

git clone https://github.com/moby/moby.git