The is a widely deployed fiber optic router (often an ONT/CPE combo) used by numerous Internet Service Providers (ISPs) worldwide, including subsidiaries of Orange , T-Mobile , and various regional carriers. Known for its dual-band Wi-Fi and VoIP capabilities, this device is the backbone of many home and small business networks.
: Never download firmware from unofficial sources or forums. Installing incorrect firmware can "brick" your device, rendering it permanently unusable. Verify Hardware Versions sagemcom f-st 5366 firmware download
If you want newer features (like better VPN support), consider putting the Sagemcom in Bridge Mode and connecting a higher-end third-party router. Check LEDs: Optus Device Guide to diagnose if the current firmware is causing issues. The is a widely deployed fiber optic router
Check the comments below (if on a forum) or contact your ISP to share which version solved your drop-out issues. Check the comments below (if on a forum)