PSCAD has undergone a number of transformations in both functionality and program architecture through the years. Sometimes, these changes alter data storage formats, or represent a complete redesign of existing features. Although changes that break backwards compatibility are avoided whenever possible, sometimes they are simply inescapable, or even inevitable.
This chapter represents a history of changes made, and how to deal with the changes if necessary, as new major and minor versions of PSCAD are released.
Changes to newer versions may even make it impossible to import much older versions of PSCAD. In these situations, for example V3 to V5, it may be necessary to update using multiple steps, stopping to debug and verify at every version level. The latest major product series, PSCAD V5, allows you to import library and case projects (*.pslx and *.pscx files) that were last saved as PSCAD v4.1 or greater, and it is mostly backwards compatible: There is a mechanism by which to save V5 projects back to v4.6 format, but not all V5 features are supported in v4.6 and may be lost during export.
NOTE: If you are a PSCAD V4 user (v4.0 to v4.2), and you want to import your projects into V5, you must first import, test and save your projects in v4.2.1. Once everything is working well, you can import directly into PSCAD V5.
This chapter discusses topics regarding the migration of projects between major versions, up to the latest PSCAD version. For more information on migrating user-defined code and other EMTDC related issues, see the section entitled Converting V2 Fortran Files in the EMTDC Manual.