The official download for DIGSI 4.90 as a standalone update has largely been superseded by newer versions on the Siemens support portal. For the most stable experience and compatibility, Siemens typically provides the "Full Version" which includes the latest service packs and device drivers. Official Download Options You can download the latest versions of directly from the Siemens Industry Online Support (SIOS)
Siemens manages its software distribution through the Siemens Industry Online Support portal. Digsi 4.90 Download UPD
Given that Siemens has moved to DIGSI 5, you might wonder if updating to 4.90 is worth it. The answer is Yes for legacy asset management. The official download for DIGSI 4
Visual Logic: Users can create logic visually using CFC (Continuous Function Chart), removing the need for deep programming knowledge. Download and Installation Requirements Is DIGSI 4
: The most recent stable version which includes the IEC 61850 System Configurator and SIGRA. DIGSI 4 V4.95 Full Version