The first version of the OpenMI standard was developed as a joint effort of several European research organizations. OpenMI stands for Open Modelling Interface and aims to deliver a standardized way of linking environmental models at run -time. In the new version of the standard several new goals were defined based on experience obtained during migration and use of the OpenMI-compliant models. This includes on one side different IT aspects such as better object-oriented design of the standard and re-use of well-known engineering practices and patterns. On the other side, after successful implementation of OpenMI in many environmental models it was also decided to extend scope of the OpenMI standard to a broader set of applications such as GIS data types, monitoring databases, running models in parallel (versus sequential pull-driven approach), improved workflow management and many others. This paper gives the details of OpenMI 2.0.