Current and recent v4 revisions:
The software system IDA-STEP was originally a result of the European funded project IDA-STEP between 2001 and 2004 with a focus on STEP AP212 (Electrical Installation) and AP214 (Automotive design). The most widely used version based on the original design was 1.4.3 from 2005.
There was a parallel development called STEP-Book that started back in 1998 with the initial focus on AP203 (configuration controlled 3D design and assemblies). Later this was heavily extended towards AP210 (Electronic assembly interconnect and packaging design) and released as IDA-STEP Electronics v2.x. Unfortunately AP212/214 on one side and AP210 on the other side had been incompatible with each other originally and as a consequence IDA-STEP v1.x was incompatible with IDA-STEP v2.x.
To overcome this incompatibility the modularization of AP210 started in 2005 that not only significantly improved AP210 but also made it interoperable with AP214. As a result we had a draft intermediate versions IDA-STEP v3.x that supported both major Application Protocols, AP210 and AP214 (and others) in parallel, but was still based on the old platform and GUI style.
With IDA-STEP v4.0 the underlying platform and GUI style had been reworked completely by switching over to Eclipse. From this point onwards IDA-STEP is a full component oriented application (called plugins) that can easily be customized for specific needs or even re-arranged to new custom applications together with other plugins provided by the customer.
Throughout all versions IDA-STEP is internally based on JSDAI for interacting with STEP-files for import and export but also as the internal data management system that is fully based on STEP data models.