"You know what this is about? Harry just wants his face back in the newspapers again. We’ve had rumours of Voldemort coming back from the Daily Prophet once a year every year."
-- Draco Malfoy (CC1.12)
A public meeting is called at the Ministry of Magic by Minister Hermione Granger, to discuss the movements of Lord Voldemort’s former allies and ask for vigilance regarding Dark Magic – all worrying signs. Giants, trolls and werewolves have been increasingly active.
This takes place after dropping off their children at King's Cross, but before Albus Potter and Scorpius Malfoy fail to appear to school - so occurs sometime during the first of September, likely to have been scheduled in the afternoon.
From the Web
Pottermore: Harry Potter and the Cursed Child
The theatre production opened in the West End of London at the Palace Theatre on 30 July 2016: Harry Potter and the Cursed Child, Parts One and Two