will the newer faster servos work with the old 80s futaba receivers? specifically a FP-R112JE Futaba receiver

yes

I've got two AE 1015 digital servos running through the exact same RX. So Yes it will.

does it means I can use digital servos with my analog receiver?

The "digital servos" can actually utilize certain features of newer radio systems.
Analog servos can have issues with certain settings on new high-end radios & run the risk of being burnt out if set wrong.
Old analog receivers will run any servo.

cool! thanks guys! nice to know...sorry for the late response though... been under mud lately...