New confirmed news about the update (it's on the official Pokemon Go Facebook page so I can't link):
Trainers,
Pokémon GO is in the process of being updated to version 0.73.1 for Android and 1.43.1 for iOS devices. Below are some release notes and comments from our development team.
• Added the ability for Trainers to spin the Photo Disc at a Gym using the Pokémon GO Plus accessory.
• Added the ability to view the number of Trainers entered, and preparing, for a Raid Battle before using a Raid Pass.
• Improved Pokémon Collection screen search functionality by allowing Trainers to search through their Pokémon’s moves using the @ character.
• Resolved a bug which caused the Raid Boss to always break free from the last Premier Ball.
• Resolved a bug that prevented Trainers from seeing they’d received double XP from Raid Battles when using a Lucky Egg.
So of course, the big ones are seeing whose in a raid before you spend your raid pass and the last ball glitch being resolved 