According to the online configurator, both the Dual Motor and Tri Motor All-Wheel Drive variants now top out at 149mph (240km/h).
That is a fairly significant drop from before, when the Dual Motor Model X could reach 155mph (250km/h) and the Plaid could reach 163mph (262km/h). (h/t: @tesla_adri)
While Tesla has not provided an official explanation for the change, it is likely due to a change in tires.
All tires have a speed rating, which sets the maximum speed those tires can safely carry a load, which includes both the weight of the vehicle and whatever might be in it (passengers and cargo).
Tires with a ‘V’ symbol on the sidewall are only rated to go 149mph, the same top speed now listed on Tesla’s website.