1. The SoC is wave-soldered directly to the motherboard, so upgrade is not possible.
2. The type and alignment of front- and back-panel connectors are unique to each NUC design, so no newer motherboards are going to fit into this chassis.
3. Only NUCs supporting enterprise management were ever sold as bare boards. No boards in your NUC design supported enterprise management, so no replacement motherboards are available for purchase.
4. Your NUC family is discontinued and no longer being manufactured or sold (other than used).
Bottom line, you can only upgrade by purchasing an entire replacement NUC.
Sorry,
...S
