You all do realize that the way the pros measure serve speed and using a radar gun are usually very different.
Pros serve speed is measured just after the ball leaves their racket
Radar guns are usually set up to measure when the ball has almost traveled to the net.
Now that 88mph serve, if it was measured closer to the net, was most likely high 90s the way the pros measure serve speed.
Völkl PB10 Mid with some strings at some tension