anchor.diff:  in zipModules ([]
   
   # usage example:
  -# ++ rename alias "services.xserver.slim.theme" to "services.xserver.displayManager.slim.theme"
  -++ rename obsolete "environment.extraPackages" to "environment.systemPackages"
  +# ++ rename alias "services.xserver.slim.theme" "services.xserver.displayManager.slim.theme"
  +++ rename obsolete "environment.extraPackages" "environment.systemPackages"
   
   # Old Grub-related options.
  -++ rename obsolete "boot.copyKernels" to "boot.loader.grub.copyKernels"
  -++ rename obsolete "boot.extraGrubEntries" to "boot.loader.grub.extraEntries"
  -++ rename obsolete "boot.extraGrubEntriesBeforeNixos" to "boot.loader.grub.extraEntriesBeforeNixOS"
  -++ rename obsolete "boot.grubDevice" to "boot.loader.grub.device"
  -++ rename obsolete "boot.bootMount" to "boot.loader.grub.bootDevice"
  -++ rename obsolete "boot.grubSplashImage" to "boot.loader.grub.splashImage"
  +++ rename obsolete "boot.copyKernels" "boot.loader.grub.copyKernels"
  +++ rename obsolete "boot.extraGrubEntries" "boot.loader.grub.extraEntries"
  +++ rename obsolete "boot.extraGrubEntriesBeforeNixos" "boot.loader.grub.extraEntriesBeforeNixOS"
  +++ rename obsolete "boot.grubDevice" "boot.loader.grub.device"
  +++ rename obsolete "boot.bootMount" "boot.loader.grub.bootDevice"
  +++ rename obsolete "boot.grubSplashImage" "boot.loader.grub.splashImage"
   
  -++ rename obsolete "boot.initrd.extraKernelModules" to "boot.initrd.kernelModules"
  +++ rename obsolete "boot.initrd.extraKernelModules" "boot.initrd.kernelModules"
   
   # OpenSSH
  -++ rename obsolete "services.sshd.ports" to "services.openssh.ports"
  -++ rename obsolete "services.sshd.enable" to "services.openssh.enable"
  -++ rename obsolete "services.sshd.allowSFTP" to "services.openssh.allowSFTP"
  -++ rename obsolete "services.sshd.forwardX11" to "services.openssh.forwardX11"
  -++ rename obsolete "services.sshd.gatewayPorts" to "services.openssh.gatewayPorts"
  -++ rename obsolete "services.sshd.permitRootLogin" to "services.openssh.permitRootLogin"
  -++ rename obsolete "services.xserver.startSSHAgent" to "services.xserver.startOpenSSHAgent"
  +++ rename obsolete "services.sshd.ports" "services.openssh.ports"
  +++ rename obsolete "services.sshd.enable" "services.openssh.enable"
  +++ rename obsolete "services.sshd.allowSFTP" "services.openssh.allowSFTP"
  +++ rename obsolete "services.sshd.forwardX11" "services.openssh.forwardX11"
  +++ rename obsolete "services.sshd.gatewayPorts" "services.openssh.gatewayPorts"
  +++ rename obsolete "services.sshd.permitRootLogin" "services.openssh.permitRootLogin"
  +++ rename obsolete "services.xserver.startSSHAgent" "services.xserver.startOpenSSHAgent"
   
   # KDE
  -++ rename deprecated "kde.extraPackages" to "environment.kdePackages"
  -
  +++ rename deprecated "kde.extraPackages" "environment.kdePackages"
   
   ) # do not add renaming after this.
  
positive.code: {pkgs, options, config, ...}:
  
  
  let
    to = throw "This is just a dummy keyword";
  
    alias = from: to: {
      name = "Alias";
  
negative.code:       if tail v != [] then zipModules v else head v
      ) list;
  
    rename = statusTemplate: from: to: with pkgs.lib;
      let
        status = statusTemplate from to;
        setTo = setAttrByPath (splitString "." to);
  