I want to use "/export compact" on automatic backup when ROS version supports it, but
give error on ROS version 5.6
Indeed, command "/export compact" is not supported on this version, but its not needed to ...

Use [:parse] to create a function, something like this:

ros code

:if ([/system resource get version] > 5.11) do={
  :global runExport [:parse "/export compact"];
} else={
  :global runExport [:parse "/export"];
}
$runExport;

thank you, that works ...