The Methods & Tools Special Interest Group met from 3 pm till 4:30 pm Central European Time.


  • Versioning: comments made by Linde Engineering

U.S. Environmental Protection Agency (represented by Bill BARRETT), AmsterCHEM (represented by Jasper van BATEN), Bryan Research & Engineering (represented by Michael HLAVINKA), Michel PONS (contractor to CO-LaN as Chief Technology Officer).


On March 8, 2023, on behalf of both the Methods & Tools Special Interest Group and the Interoperability Special Interest Group, Michel PONS submitted to CO-LaN Management Board version 1.20 of the document describing the CAPE-OPEN versioning scheme proposed by both SIGs. Comments were requested as well as a way forward with the document.

On March 13, comments were received from Linde Engineering.

Methods & Tools SIG dedicated its weekly meeting to the analysis of the comments made and to the development of  appropriate answers to these comments. Version 1.21 of the document was developed today with the objective to explain especially why the chosen versioning approach modified the Semantic Versioning approach, and why both SIGs think that it is appropriate for CAPE-OPEN.

In the chosen versioning approach, breaking changes are split between major breaking changes and minor breaking changes, represented through the first two digits of the CAPE-OPEN version number, instead of considering that minor changes, as in Semantic Versioning, are non-breaking changes.

Major CAPE-OPEN (breaking) changes are impacting the entire standard made of many, often independent, interface specifications. Minor CAPE-OPEN (breaking) changes are focusing typically only on one of these interface specifications. There is partly a “marketing” reason to this split: making most changes to the first (major) version number could be considered as a sign of very significant work for adopters. This approach is also linked to the history of distribution of CAPE-OPEN Types, especially for COM middleware, using Type Libraries. The versioning of these rely only on the first two digits in the version number.

Compared to the Semantic Versioning approach, feature additions were lowered a level in the digit hierarchy of the CAPE-OPEN version number. Flowsheet Monitoring and Custom Data are extensions (feature additions) to the CAPE-OPEN standard, and these are not introducing any breaking change in the CAPE-OPEN standard. Their adoption is encouraged but non-mandatory. It reflects the progressive extension of CAPE-OPEN to other aspects of process simulation, while retaining existing features of the CAPE-OPEN standard.

The modifications brought to the document in its version 1.21 will be reviewed by both the Methods & Tools SIG and the Interoperability SIG. Next meeting of Methods & Tools SIG is scheduled for March 21, 2023.


Picture of Bill BARRETT (US EPA representative) in December 2018Contact Bill BARRETT (representative of US Environmental Protection Agency, leader of the Methods & Tools Special Interest Group) should you wish to join the Methods & Tools Special Interest Group. Its charter is: “Improve integration, and expand utilization of Computer-Aided Process Engineering (CAPE) applications within the enterprise through identification and resolution of existing cross-cutting issues with the CAPE-OPEN platform, develop mechanisms for use of CAPE within other application domains, and incorporate advances in information technology into the CAPE-OPEN platform.”