 ALLENTOWN, Pa. LAS VEGAS--BUSINESS WIRE--- FOUR--Shift4 Payments NYSE: FOUR, the leader in integrated payment processing solutions, today announced that it will release its first quarter 2021 financial results before market open on Thursday, May 6, 2021. Management will also host a conference call on the day of the release May 6, 2021 at 8:30 am ET to discuss the results. To register for this conference call, please use this link After r 