New information from today's Global stream:
Version 3.4 is confirmed to be the first Laboratory Chapter (AKA the first part of the P5R collab), and add Violet. As usual, Violet is getting various buffs compared to her current abilities in other regions
The song Take Over will be added to the music club minigame
The Persona Sraosha will be added to the medal exchange shop
"Kasumi" Yoshizawa and Yaoling Li will be added to Tycoon, along with the start of a new Tycoon season
Rerun banners for Oracle and Noir will begin on the 26th
New Phantom Pass begins
As previously implied, the start of Mayumi Hashimoto (Turbo)'s Synergy will be added
Version 3.5 will add the rest of Mayumi's Synergy, as well as adding Turbo as a playable character (Turbo will eventually be added to the standard/permanent contract, presumably around September?) - Turbo's banner has a special feature:
Turbo's Thieves Secrets battles will be added as well
The rest of Chizuko Nagao's side story will be added
Another Trial of Thorns event
Rerun banner for Cherish starting on April 9th
They also shared a simple roadmap that essentially confirms the second (and final) Laboratory Chapter, as well as Crow, will be in Version 3.6: