Here you can see what is new in various versions of CPN Tools and Access/CPN and which versions of Access/CPN works with which versions of CPN Tools. The list is not necessarily comprehensive, but lists the major changes.

The list may also reflect features in versions of CPN Tools that have not yet been publicly released, and as such reflects changes that are currently in the source repository but have not yet been deemed important enough to make a general release.

CPN Tools


  • New simulator compiled with SML/NJ 110.78 and Cygwin from February 2015


  • Enable DCR graphs (NOTE: This feature has several known issues, including breaking Declare in some cases)
  • Check the list of known issues


  • Make Declare constraints work with groups


  • Make Declare constraints honored during fast forward
  • Improved Declare performance after fast forward


  • Fix PNML export for arc weights and reset/inhibitor arcs
  • Handle layering correctly after closing a sheet
  • Improved printing of aux shapes created using the external API


  • Fixed wrong bounding box for printing with collapsed current marking
  • Fixed partial state-space problems with automatic progression
  • Don’t start text editor on constraints


  • Fixed cloning Declare constraints
  • Fixed deleting Declare constraints
  • Fixed (disabled) interplay between Declare constraints/reset arcs/inhibitor arcs and substitution
  • Graphical improvements cloning reset/inhibitor arcs
  • Fixed bendpoints for Declare constraints
  • Fixed drawing problems when deleting Declare constraints
  • Declare constraints are now checked incrementally


  • Load/save Declare works
  • Fixed last Declare constraints
  • Option for setting memory for simulator extensions
  • NOTE: Models using Declare saved using previous versions are not compatible with this version! Such models will not be compatible with any future version.


  • Much improved support for Declare
  • Fix Rayleigh and Weibull distributions


  • Add labels from external sources
  • Model statistics (tool tip on model name in index)
  • Improved aux graphics
  • Allow extensions to add instruments
  • Re-expose ogpath and ASAP options
  • Fixed a bug causing the cursor to blink in weird ways
  • The linux simulator is back


  • Drawing primitives
  • Minimize extension server to tray
  • On-demand activation of extensions


  • Support for intinf and time color sets
  • Experimental support for real color sets. Please read this page before using this or asking for support!!


  • More intuitive load/save from palette
  • Save net as PNML.
  • Automatic snap to grid
  • Remove guide grid and place kinds


  • More control over simulation options for fast forward simulation (total number of steps, end time)
  • Added the weibull distribution.
  • Time-equivalence reduction for state space analysis.
  • Ranges supported for time stamps (using extensions).
  • No longer fails if extensions are not started.


  • ONLY USE THIS VERSON TO TEST SIMULATOR EXTENSIONS It does not yet gracefully degrade if you don’t! You will not be able to create nets without extensions, and extensions are not yet optimized, making this version seem significantly slower.
  • Preliminary support for simulator extensions.


  • More graphical tweaks (improved graphical feedback when drawing, e.g., double arcs, port-type + place kind instruments, bounded and ordered places, some dependency highlights)
  • Switch to UserVoice for support/bug-tracking reflected in UI
  • Show time used to do long simulation/compute state-space
  • Preliminary support for DRAWING Declare constraints
  • Fixed printing of inhibitor/reset arcs
  • Support for (uncolored) reset arcs
  • Support for (uncolored) inhibitor arcs; demo of inhibitor and reset arcs.
  • (Temporarily) removes Linux simulator; incompatible with past and future versions of CPN Tools and Access/CPN
  • Cascade State-space commands.


  • Graphical tweaks (for port places, arcs, binders + sheets, background)
  • Improved support for working with low-level nets.
  • Preliminary support for DRAWING inhibitor + reset arcs
  • Preliminary support for DRAWING ordered + bounded places


  • Added the rayleigh distribution.
  • Bugfixes


  • Fix regression in discrete so the upper bound was never returned.


  • In the 3.2 series the alias sort was introduced for color or colset in declarations; this however broke function using a sort function, and so has been reverted.


  • Names with parentheses gave wrong output when exported to EPS.
  • Improved error reporting when computing state space.
  • Reduced download size from 30 MiB to 16 MiB by moving Mac OS X and Linux to on-demand downloaded packages.
  • Fixed regression in 3.3.0 breaking (at least) timed color sets.
  • Fix for (at least some) problems with paths containing non-ASCII characters.


  • Fix error reporting for declarations
  • Use new experimental feature of SML/NJ which provides improved error messages.
  • Fixed bug sometimes causing the first declaration to appear unchecked (and having some consequences when making certain edits). If you haven’t encountered any obscure problems, this did not affect you.


  • Expose random number generator structure RandomValues, which allows users to reset the random number generator to make reproducible experiments.
  • Make random distribution functions use same seed as standard random number generator.
  • Add gamma and beta distributions.
  • Fix a bug which caused instances of the first enabled transition instance to have slightly higher probability of being chosen and instances of the last slightly lower when using global binding element fairness. Especially visible if you have just two transitions with one enabled binding, where one would be starved if the other was always enabled.
  • When using global binding element fairness, sometimes the transition would appear more than once in the simulation report.


  • Fix bug with real time stamps.


  • New notions of fairness available as an option.
  • Simulation is 10%-15% faster.
  • CPN Tools is now open source.
  • Bugfixes.
  • Breaks compatibility with the BRITNeY Suite. Support will most like not be reintroduced. We advise using Access/CPN instead.


  • Fix the contains_all function.
  • Make CPN Tools monitors play nicer when running the simulator on another computer.


  • Fix DTD location in saved files.
  • Add HomePredicate state space query function.
  • Fix bug when single-stepping thru hierarchical model.


  • Fix crash when deleting place with a current marking.
  • Significantly smaller download.


  • Fix for guards containing record accessors.
  • Fix problem entering state-space tool when a union color set used an element no (like colset NO = with no).
  • Save debug information correctly.
  • Safe mode, which avoids using accelerated graphics, making CPN Tools play much nicer with (at least) Parallels Desktop for Mac OS X.


  • New simulator which is up to twice as fast for both simulation and state-space analysis.
  • Improved support for modern computing environments, especially 64-bit Windows and running under virtual machines.
  • Support for transition priorities.
  • Support for real values in time stamps.
  • Numerous bug-fixes.
  • Drop support for GUI on Windows, introduce support for simulator on Windows, Linux, and Mac OS X.


Next Version

  • Fix for exporting nets of depth > 2 (thanks to Robert Kranz for the fix)


  • Improved handling of monitors
  • Better handling of starting simulator; should work in packaged jars and Eclipse workspaces on all platforms.
  • Update for CPN Tools 3.4.0


  • Minor change to textual representation of page instances


  • Update for CPN Tools 3.3.1


  • Update for CPN Tools 3.3.0


  • Vastly improved exporter to CPN Tools (thanks in part to Dirk Fahland)
  • Support for loading and checking monitors (EXPERIMENTAL)


  • Update to be compatible with CPN Tools 3.2.2.
  • Facilitate synchronization on Execution Context.
  • Improved handling of (integer) time during cosimulation.
  • Better support for loading while not connected to the internet (thanks to Stephan Schweig)
  • Better support for running from source (thanks to Stephan Schweig)
  • Improved export to .cpn files (including automatic layout if desired)


  • Update to be compatible with CPN Tools 3.2.1.
  • Fix discrepancy between Java code and included simulator.


  • Update to be compatible with CPN Tools 3.2.0.
  • Include support for cosimulation.
  • Tons of bugfixes and feature enhancements.


  • Initial Release. Access CPN models (load and simulate) from Java applications.



  • Initial Release. Automatically grade many CPN models against one specification. Also logic-based testing of CPN models.
Knowledge Base

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