Its basic MTOW was increased to before offering a possible version. Its 316 t MTOW appeared in 29 May 2018 update of its type certificate data sheet. This raised its range from . A further MTOW increase by 3 t to 319 t is under study to be available from 2020 and could be a response to Qantas' Project Sunrise. Initial speculation suggested that the variant might be marketed as the A350-1000ULR. However, the -1000 is not expected to share the -900ULR's larger fuel tanks and other fuel system modifications, and Airbus has stopped short of describing the largest MTOW variant as a ULR model, despite the range. In December 2019, Qantas tentatively chose the A350-1000 to operate their Project Sunrise routes, before a final decision in March 2020 for up to 12 aircraft. In November 2019, maximum accommodation increased to 480 seats from 440 through the installation of new "Type-A+" exits, with a dual-lane evacuation slide. Airbus has explored the possibility of a further stretch offering 45 more seats. A potential 4 m stretch would remain within the exit limit of four door pairs, and a modest MTOW increase from 308 t to 319 t would need only 3% more thrust, within the Rolls-Royce Trent XWB-97 capabilities, and would allow a range to compete with the Boeing 777-9 capabilities. This variant was to be a replacement for the Boeing 747-400, tentatively called the A350-8000, -2000 or -1100. Within the June 2016 Airbus Innovation Days, chief commercial officer John Leahy was concerned about the size of a 400-seat market besides the Boeing 747-8 and the 777-9 and chief executive Fabrice Brégier feared such an aircraft could cannibalise demand for the -1000. The potential aeroplane was competing against a hypothetical 777-10X for Singapore Airlines. At the 2017 Paris Air Show, the concept was shelved for lacking market appeal and in January 2018 Fabrice Brégier focused on enhancing the A350-900/1000 to capture potential before 2022/2023, when it will be possible to stretch the A350 with a new engine generation. The -long A350-800 was designed to seat 276 passengers in a typical three-class configuration with a range of with an MTOW of . In January 2010 Airbus opted to develop the -800 as a shrink of the baseline -900, avoid a specific development and increasing its payload by or its range by but leading to a fuel burn penalty by "a couple of%" according to John Leahy.