It think they get asked about a lot in interviews it sounds like its been intermittently worked on over the last years between there quite heavy tour schedule they never seem to use the word finished - But id take a guess they probably want to drop it prior to the next festival season - So yeah late april/may would. make a lot of sense
Travis Scott / Biffy Clyro
Chappell Roan / Hozier
Muse or Eminem / Central Cee
The only one I'm unsure on is Muse, if not them then Eminem but I don't know if they would have 3 rap headliners in a year
The Stones played 2 nights at BST at Hyde Park in the weeks after the festival and were selling a DVD of it later that year (which I got brought for Xmas) so thats why they didn't want their full set televised I believe
The only artists announced for the Nordic festivals in August that I am excited about are Fontaines dc and MJ Lenderman and both are at Primavera. This is the disadvantage of drip feeding the lineup. Might skip WoW this year unless they bring out some stronger undercard additions later on.