The update does not change anything except the class name for the share button icon, so you will not see a difference right away. The default is to keep the same link icon as before (link).
You can tell the update is done if you browser inspect the button and it includes the class d-icon-d-post-share (before the update the class was d-icon-link)
You have to edit your theme header as described here Substitute Link Icon Only For Sharing - #22 by ondrej