Siemens S7 TCP OPC UA Server Release Notes

A summary of updates to the Siemens S7 TCP OPC UA Server, including new features, improvements, and bug fixes. Use this page to track changes that may affect system operation and integration.

v3.14.0

16 Apr 2026

Install →

Bug fixes:

Fixed an issue in the caching mechanism that could, in rare cases, incorrectly trigger a cache miss. As a result, clients could receive a "no data" error even though valid data was already available in the server cache.

v3.13.0

14 Apr 2026

Install →

This release serves as a baseline milestone representing the current state of the Siemens S7 TCP OPC UA Server. Starting with version 3.13.0, all subsequent releases are published on dpaxt.com.
Previous releases introduced a major redesign of the S7 TCP/NCK protocol implementation. The communication stack was rearchitected around an asynchronous processing model, with significant improvements to the transport layer, transaction handling, caching, and request scheduling. Support was expanded for multiple Siemens memory areas, including DB, M, I, Q, C, and T, while batch read operations were optimized and resilience against protocol errors and malformed device responses was significantly improved.
The interaction capabilities with CNC systems were also substantially extended. Support was added for file operations, including file upload, download, and management, together with efficient handling of large files. Connection state management and failure recovery were improved, providing more reliable session handling, proper cleanup of monitored items, and more robust automatic reconnection.
At the platform level, numerous improvements were made to enhance stability and portability. These include service optimizations, memory management fixes, updated build pipelines, and full support for Linux and Docker deployments.