IEC 62541-5:2020 defines the Information Model of the OPC Unified Architecture. The Information Model describes standardized Nodes of a Server’s AddressSpace. These Nodes are standardized types as well as standardized instances used for diagnostics or as entry points to server-specific Nodes. Thus, the Information Model defines the AddressSpace of an empty OPC UA Server. However, it is not expected that all Servers will provide all of these Nodes. This third edition cancels and replaces the second edition published in 2015. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) Added Annex F on User Authentication. Describes the Role Information Model that also allows configuration of Roles. b) Added new data types: "Union", "Decimal", "OptionSet", "DateString", "TimeString", "DurationString", NormalizedString", "DecimalString", and "AudioDataType". c) Added Method to request a state change in a Server. d) Added Method to set Subscription to persistent mode. e) Added Method to request resending of data from a Subscription. f) Added concept allowing to temporarily create a file to write to or read from a server in C.4. g) Added new Variable type to support Selection Lists. h) Added optional properties to FiniteStateMachineType to expose currently available states and transitions. i) Added UrisVersion Property to ServerType. This version information can be used for session-less service invocation.