v4.18.0
Author's note: While technically this is a breaking change, it's only removing an internal API (made for final-form-array) on a Monday morning that was first published less than 48 hours earlier, on Saturday afternoon. If you spent all day Sunday rewriting a project to use the ultimately unneeded forceUpdate API, then I do sincerely apologize. You should change fieldState.forceUpdate=true to fieldState.lastFieldState=undefined to get the same effect. Feel free to yell at @erikras on Twitter if not bumping the major version number for this release outrages you.