error "unsupported Eagle version"
      }
    } elseif {$language eq "tcl"} then {
      if {$version ne "8.4" && $version ne "8.5" && $version ne "8.6"} then {
        error "unsupported Tcl version"
      }
    } elseif {$language eq "client"} then {
      if {![regexp -- {^1\.0(?:\.\d+)+$} $version]} then {
      if {![regexp -- {^1\.0(?:\.\d+){0,2}$} $version]} then {
        error "unsupported client version"
      }

      set isClient true
    } else {
      error "unsupported package language"
    }