If your device is still running 2.3.5 and never received its final manufacturer update (often to 2.3.6), you can try the following:
: Some older devices required computer software to update. For example, Samsung users once used Samsung Kies to flash final versions manually. Modern Risks of Using Android 2.3.5 system update for android 2.3.5 download
System Update for Android 2.3.5 Gingerbread: Is a Download Still Possible? If your device is still running 2