Originally Posted by alcjphil

You would need a 10 speed cassette, 11 speed cogs are too close together for it to work. Cassette has to match the number of speeds in the shifter

Originally Posted by gsa103

4700-shifters, 10-speed cassette (any), 11-speed rear mech -- Works, all 10 cogs used.
4700-shifters, 11-speed cassette, 11-speed rear mech -- Doesn't work
5800-shifters, 11-speed cassette, 4700-rear mech -- Works