OPC Unified Architecture (OPC UA) is the most recent of all OPC specifications and unifies them all into one. OPC UA provides all the capabilities of the current OPC specifications and is even backwards compatible with current specifications. OPC UA also adds various capabilities that were unavailable in previous specifications. OPC UA enables programmers to select various data transportation methods such as COM, DCOM, or .Net (using XML to enable communication with operating systems other than Windows, or binary encoding to gain significant speed).

OPC UA also enables users to take advantage of various information models to transfer data as simple as a temperature reading to as complex as a work order. OPC UA also enables vendors to specify their own custom information models.

The OPC Foundation (www.opcfoundation.org) is responsible for defining and maintaining the OPC UA specification.