Based on the results of another survey, phase #4, which was successfully completed in September 2023, focused on further improvements of the open62541 community project. One set of features developed in this project phase concentrated on flexibility and usability. This includes the so called "nodesetLoader", which allows to load and store the information model at run time through a XML based configuration. Furthermore, users can now select the companion specification in the build system and the server configuration can be based on a JSON file. The implementation of the “OPC UA Reverse Connect” extends the application range of open62541 to protected networks in which no incoming connections are permitted. And an analysis of potential optimizations for resource constrained devices opens the ground for new fields of application as well. In addition to many other minor improvements, a significant step has also been taken in the implementation of the PubSub state machine.