Custom ROMs can take you up to Android 7.1 (Nougat) or even 9.0 (Pie) — with improved performance and app compatibility.
Settings → About tablet, or open the case (for TV boxes). Rk3188 Android Update LINK
The largest repository for Rockchip firmware remains . Post #1 in their "RK3188 ROMs" thread contains a live MEGA link to a compilation of: Custom ROMs can take you up to Android 7
Updating your RK3188-based Android device—whether it's a TV box, tablet, or car head unit—requires specific firmware files and specialized flashing tools. Because this chipset is older, official OTA (Over-the-Air) updates are no longer released, and you must manually flash the software using a PC. Rk3188 Android Update LINK