This new version brings the earlier separate products, QuickOPC.NET, QuickOPC-COM and QuickOPC-UA, in a single installation package. The product editions has been simplified: Now the editions are not distinguished by the platforms or OPC specifications they support. Instead, the price list has been greatly reduced by a unification into a QuickOPC product, with just two editions: Standard and Ultimate. The editions differ mainly in availability of advances features, such Live Mapping, or a support of reactive programming model.

Version 5.21 also brings OPC-UA features in QuickOPC to the same functionality level as OPC "Classic". Features like OPC browsing dialogs, Live Mapping and Live Binding (visual binding to Windows Forms controls) are now all available for OPC Unified Architecture (OPC-UA) connections as well.