: V5.4 SP2 HF1 is fully backward compatible with older STARTER versions.
: Projects created in older versions (like V4.x) are typically compatible, but projects from versions (like V5.5) cannot be opened in V5.4. SSP Packages sinamics starter v54 download full
: If you have a project created in an older version (like V5.4.0.1) and it fails to open in V5.4.2.1, it may be due to project corruption rather than version incompatibility; Siemens recommends always working with archived versions to prevent this. sinamics starter v54 download full