What upgrades have F1 teams brought to Barcelona?

-RedBull

 RedBull brought minor upgrades for their floor edge and diffuser. The top corners of the diffuser are now more curved and which will affect their local load and performance. the second upgrade is a reshaped floor edge that will suit local pressures while maintaining aerodynamic stability.

-Ferrari 

 Ferrari brought major upgrades which will be interesting to lookout. But Carlos Sainz is cautious that Ferrari's upgrades will 'not change our lives' between races. 

they brought a track-specific rear wing which will help them to cover the aerodynamic efficiency required for this track. but the important upgrade is their new sidepod which will develop the flow conditioning towards the rear wing and cooling flow management.

-Aston Martin

Astons brought quite extensive upgrades for their front wing end plate which has a less aggressive design and flaps are redesigned to give the best aerodynamic efficiency.

-Mercedes 

they brought their new sidepod concept to Monaco but due to the track surface, they couldn't gather enough data. So they are here to test if their new concept is reaching the expectations or not. They were just satisfied to bring minor changes to their diffuser side wall.

-Williams 

Williams just brought track-specific changes for their front wing flop and engine cover which now has an optional exit for the central cooler

-Alpha Tauri 

AlphaTauri brought a new rear wing for this weekend. Compared to the previously raced rear wing this farther refinement aims more downforce.