Mercedes explains the six improvements brought to Monaco
Mercedes has detailed the extent of the improvements made on the W14 at the Formula 1 Monaco Grand Prix.

After a disappointing start to the season with their new W14, Mercedes worked tirelessly in their Brackley factory to make a series of modifications to the car. While seeking to improve the downforce of the car through the latest developments, Mercedes has endeavored to provide their drivers with a more consistent and stable platform.
That is why, beyond the obvious visual changes made to the sides, the front suspension and the floor have also been modified.
As part of the F1 regulations, teams must inform the FIA of any technical modifications made to their cars and explain the reasons behind these changes. Prior to the Monaco GP, Mercedes duly informed the FIA of the six main modifications made to their car and the reasons that prompted them. The modifications are as follows:
Front Suspension: The upper front triangle arm has been raised. This change allows for better positioning of the triangle wake, which improves the airflow over the side, and therefore the cooling performance.
Floor edge: A change in the local load has been made to the floor camber, resulting in increased local load and improved flow towards the diffuser. This should increase rear downforce.
Air intake: A wide and high intake on the side gangway improves the flow towards the edge of the floor, increasing the floor load and also enhancing the flow towards the rear suspensions.
Flanks and bodywork: Increasing the width of the bodywork enhances downforce and also improves flow towards the rear wing.
Rear wing: Increasing the curvature of the rear wing flap results in an increase in downforce on the rear wing, which reduces the pressure at the rear of the car, thereby increasing the downforce on the rear of the underbody.
Aero rear brakes: A second series of tin fins added to the existing row of fins, which increases downforce. This also reduces the pressure behind the lower suspension arms, thus increasing the downforce on them.