For official firmware files, you should visit the Sagemcom Support Portal .
Because firmware is ISP-specific, you should visit your provider's help page for the most accurate version info: sagemcom f-st 5366 firmware download
Compare your current "Software Version" with the latest known versions discussed in community forums like r/nbn on Reddit . Why You Can't Usually Download the Firmware File For official firmware files, you should visit the
If your ISP provides a manual firmware file (rare for this model), ensure: For official firmware files