Major reorganization of opm modules have taken place in preparation for the next release:

• The opm-core module has been removed, its contents moved to appropriate locations in other modules.
• The opm-parser and opm-output modules have been folded into the opm-common module. If you do not need these features, there are build-system options for opm-common that allow you to build without them: set ENABLE_ECL_INPUT to false to not build the Eclipse deck parser feature, and/or set ENABLE_ECL_OUTPUT to false to not build the Eclipse binary I/O feature. Both of these default to true, and setting them to false will disable building some downstream programs such as Flow.

The new structure is shown on the module page.