diff -ur openssh-8.4p1.orig/ssh_config openssh-8.4p1/ssh_config
--- openssh-8.4p1.orig/ssh_config	2021-01-27 14:43:22.698144889 +0100
+++ openssh-8.4p1/ssh_config	2021-01-27 14:40:46.170143382 +0100
@@ -17,6 +17,12 @@
 # list of available options, their meanings and defaults, please see the
 # ssh_config(5) man page.
 
+# To modify the system-wide ssh configuration, create a "*.conf" file under
+# "/etc/ssh/ssh_config.d/" which will be automatically included below.
+# Don't edit this configuration file itself if possible to avoid update
+# problems.
+Include /etc/ssh/ssh_config.d/*.conf
+
 Host *
 #   ForwardAgent no
 #   ForwardX11 no
diff -ur openssh-8.4p1.orig/sshd_config openssh-8.4p1/sshd_config
--- openssh-8.4p1.orig/sshd_config	2020-09-27 09:25:01.000000000 +0200
+++ openssh-8.4p1/sshd_config	2021-01-27 14:21:23.070132184 +0100
@@ -10,6 +10,12 @@
 # possible, but leave them commented.  Uncommented options override the
 # default value.
 
+# To modify the system-wide sshd configuration, create a "*.conf" file under
+# "/etc/ssh/sshd_config.d/" which will be automatically included below.
+# Don't edit this configuration file itself if possible to avoid update
+# problems.
+Include /etc/ssh/sshd_config.d/*.conf
+
 #Port 22
 #AddressFamily any
 #ListenAddress 0.0.0.0