Yoda recognized R2-D2 in The Empire Strikes Back. 1 / 7
He notices the droid as Anakin's old friend when R2 and Luke arrive on Dagobah. 2 / 7
Yoda and R2 were both very active with the Republic during the Clone Wars. 3 / 7
Yoda found it obvious Luke was traveling with Anakin's old droid. 4 / 7
It's unknown if R2 recognized Yoda as well, but he didn't have his memory wiped. 5 / 7
In all likelihood, R2 knew it was Yoda when he saw him. 6 / 7
It's cool that Star Wars canon has cleared this issue up. 7 / 7