• $SCRIPT was renamed to $CHROOT_SCRIPT. $SCRIPT can still be used
  but is considered deprecated.
• Added RuntimeTrees= setting to mount directories when booting images
  via mkosi boot, mkosi shell or mkosi qemu. The directories are
  mounted with a uid map that maps the user invoking mkosi to the root
  user so that all files in the directory appear as if owned by the root
  user in the container or virtual machine and any new files created in
  the directories are owned by the user invoking mkosi. To make this
  work in VMs, we use VirtioFS via virtiofsd. Note that this
  requires systemd v254 or newer to be installed in the image.
• Added support for booting directory images with mkosi qemu via
  VirtioFS. When CONFIG_VIRTIOFS and CONFIG_VIRTIO_PCI are builtin
  modules, no initramfs is required to make this work.
• Added Include= or --include to include extra configuration files
  or directories.
• Added support for specifiers to access the current value of certain
  settings during configuration file parsing.
• mkosi will now exit with an error when no configuration was
  provided.
• Multiple scripts of the same type are now supported.
• Custom distributions are now supported via the new custom
  distribution. When using custom as the distribution, the rootfs must
  be provided via base trees, skeleton trees or prepare scripts.
• We now use local GPG keys for rpm based distributions if the
  distribution-gpg-keys package is installed on the host.
• Added RuntimeSize= to grow the image to a specific size before
  booting it when using mkosi boot or mkosi qemu.
• We now set MKOSI_UID and MKOSI_GID when running scripts which are
  set to the uid and gid of the user invoking mkosi respectively. These
  can be used to run commands as the user that invoked mkosi.
• Added an Architecture= match
• Initrds specified with Initrds= are now used for grub menuentries as
  well.
• ImageId= and ImageVersion= are now written to os-release as
  IMAGE_ID and IMAGE_VERSION if provided.
• We pass command line arguments passed to the build verb to the build
  script again.
• We added support for the "RHEL Universal Base Image" distribution.