This version is intended to be the last release of the 5.x series. The main purpose of this release is to make it possible to write model code, primarily NED, which is also compatible with the upcoming OMNEST 6.0. It also contains several bug fixes backported from the 6.0 branch.

For compatibility with 6.0:

  • NED: support for "" syntax of parameter references (and other references too, see below) in expressions. Using the "parent" qualifier is only allowed inside submodule and connection blocks (within the curly braces), but not on compound module level. This change is necessary for being able to write NED files which are compatible with both OMNEST 5.7+ and 6.x. The interpretation of parameter references in expressions have changed in 6.0. In 6.0, a "foo" parameter reference in a submodule means the parameter of the same submodule (""), while in 5.x it means the parameter of the enclosing compound module (which would be expressed in 6.0 as "").

    The way to write NED files compatible with both is to always explicitly qualify the parameter with "this" or "parent". In a NED file written for 5.x, prefix plain parameter references inside subcomponent curly brace blocks with "parent." to ensure that their meaning doesn't change in version 6.0.

    The same change applies to submodule and gate references as well, e.g. in the argument of exists() and sizeof().

    The change also affects the interpretation of references in expressions that occur in ini files.


    network Network {
       node: Node {
         foo = foo; // CAVEAT: means "" in 5.x, "" in 6.x!
         bar =;  // OK: unambiguous, recognized by all versions
         faa =;  // OK: unambiguous, recognized in 5.7 and 6.x
         baz =;  // CAVEAT: means "" in 5.x, "" in 6.x!
         bax =;  // OK: unambiguous, recognized in 5.7 and 6.x
  • MatchExpression: added 'field =~ pattern' syntax as alternative to 'field(pattern)'

  • Added Ws, Wh, kWh, MWh to the list of recognized measurement units


  • Statistic recording: Added a way to disable auto-adding of the warmup filter. One needs to specify "autoWarmupFilter=false" in the @statistic for that. This opens the possibility for the user to add warmup filters to a custom place, not just before all other filters. E.g. consider "min(warmup(foo))" (which is produced by auto-adding of the warmup filter), and "warmup(min(foo))" which might be what the user wants instead.

  • Fingerprints: Fixed a bug in cHasher::add(const char *) which caused some bits in the input not affect the fingerprint. This bugfix does not affect the fingerprint of most simulations, because very few fingerprints use strings as input.

  • Canvas: In cPathFigure, path parsing was refined: If an op char is missing, assume previous one, in accordance with the SVG specification.

  • cHistogram and histogram strategy classes: work around several problems caused by the finite precision of 'double'.

  • Miscellaneous other bug fixes.


  • Added Fake GUI mode. Fake GUI means that refreshDisplay() is called periodically during simulation, in order to mimic the behavior of a graphical user interface like Qtenv. It is useful for testing simulation models with visualization using Cmdenv, e.g. in smoke or fingerprint tests. Fake GUI can be enabled with the cmdenv-fake-gui=true configuration option.

    The set of currently supported options for Fake GUI:


  • Added Ctrl+W as shortcut for closing toplevel inspector windows.

  • Made the "Run" and "Fast" buttons "pop out" (and stop simulation) if triggered again. This adds a radiobutton-like behavior to these actions, which is handy for running the simulation for a very short time, with a single button.

  • Log Inspector: Perform "find" on plain text comment, i.e. ignore formatting escape sequences.

  • Log Inspector: After a search, scroll the found text into the middle of the viewport instead of just to the edge.

  • Find dialog: Select the entire searched text when opening the find dialog, to allow easier and quicker typing of a different query.

  • Further bug fixes.


  • JsonExporter: Fix: In the exported file, result items appeared under multiple runs due to missing filtering. Applies to both the IDE and opp_scavetool.

  • In the Simulation Manual, the section about opp_scavetool was out of date.

Simulation IDE:

  • Welcome screen theme changed (circle -> solstice) due to problems with dark theme with the old 'circle' theme.

  • The Download Simulation Models dialog now supports specifying a custom project name and location. Also, the default project name is now coming from the downloaded descriptor file (not from the .project file in the archive.)

  • Fixed the download issues in the Download Simulation Models dialog.

  • NED, Ini Editor: Syntax highlight for the NED "parent" keyword

  • Ini Editor: group fingerprint and fakegui-related fields on a separate new form page.

  • NED Editor: Fix rendering issue with the mouse cursor for the creation tool in the palette.

  • Launcher: Print working directory and command line to console when debugging simulations, similar to the simple "run" mode launch.

  • Launcher: On macOS, use lldbmi2 for debug launches by default.

  • Makefile generation brought in sync with omnetpp-6pre11.


  • Use Eclipse 4.21, and JustJ as the private JRE.

  • Use python3 as the interpreter for Python scripts.

  • opp_makemake: Makefile generation brought in sync with omnetpp-6pre11.

  • Got rid of a few bison warnings and properly test for Bison 3.

  • Fixes for the Windows build.

  • Updated bundled sqlite3 amalgamation sources.

What's New in OMNEST 5.6.2