United Parcel Service Inc. and the Teamsters agreed to extend their current labor contract past its July 31 expiration to wrap up 38 supplemental accords with locals, the union said. The extension doesn’t have an end date, but negotiators expect to conclude all talks within two months, said Denis Taylor, co-chairman of the Teamsters National UPS Negotiating Committee. Company and union officials reached a tentative master agreement about three weeks ago.