Change record status: 
Project: 
Introduced in branch: 
10.1.x
Introduced in version: 
10.1.0
Description: 

The Drupal\Core\Entity\Controller\EntityController class constructor now takes a route_match system object as a parameter. For BC reasons this parameter is optional, however, the optional usage is deprecated and will become required in Drupal 11.0.0.

Any sub-classes of the Controller will need to update their constructor accordingly.

Impacts: 
Module developers
Site templates, recipes and distribution developers