DUBAI, Nov 16 (Reuters) - Boeing still plans to deliver the first of a revamped version of its 777 long-haul jet in mid-2020, a senior executive said on Saturday.

Plans for the new 777X have been received "very positively" by all three major Gulf airlines, Marty Bentrott, senior vice president for international sales, told a news conference.

A U.S. union leader has said talks with Boeing that led to a contract proposal voted down by union members last week had been driven by a decision to "expedite development" of the 777X, because of the success of a competing Airbus plane.

"There is no change of schedule," Bentrott said, adding that talks with the union had begun in March.

Boeing meanwhile expects to turn the corner on reliability problems with the 787 Dreamliner within six months as a result of software changes, he said. Customers including Qatar Airways and Norwegian Air have complained about the plane's reliability.