Ifupdown now comes with a systemd service file. Any options specified in
/etc/default/networking will no longer be used. If you are using
CONFIGURE_INTERFACES=no, then run "systemctl disable networking" instead.
If you are using EXCLUDE_INTERFACES, then edit /etc/network/interfaces and
remove those interfaces from any "auto" keywords.
Ifupdown will now be more strict when errors occur, and will also properly
return a non-zero exit code when (de)configuring an interface fails. Please
ensure your /etc/network/interfaces is correct and that your interfaces can
be brought up and down without errors, especially during system startup.
Ifupdown now has more fine-grained locking, allowing concurrent calls of
ifup and ifdown. It is also allowed to call ifup and ifdown from a (pre-)up
or (post-)down line from /etc/network/interfaces, as long as no recursion
You can now use the "inherits" keyword to copy settings from another
RFC 4361 DDNS support is now enabled by default for inet dhcp interfaces if
isc-dhcp-client is installed.