Tenda has discontinued the D305 model. It is no longer listed on most official regional Tenda websites (e.g., Tenda Global, Tenda US). Direct download links, if still hosted, are often found on legacy support pages.
If your internet is stable, your Wi-Fi works fine, and you don’t have security concerns—you may not need the update. However, if you experience random reboots, DNS issues, or sluggish performance, finding the correct and installing it is a smart, free fix. tenda d305 firmware update link