Change record status: 
Project: 
Introduced in branch: 
8.9.x
Introduced in version: 
8.9.0-beta3
Description: 

The Composer plugins provided by Drupal -- the scaffold plugin, the vendor hardening plugin, and the project message plugin -- are now compatible with Composer 2.

Additionally, Drupal now requires composer/installers version 1.9 or later, as earlier versions are not compatible with the Composer 2 plugin API.

Impacts: 
Site builders, administrators, editors
Updates Done (doc team, etc.)
Online documentation: 
Not done
Theming guide: 
Not done
Module developer documentation: 
Not done
Examples project: 
Not done
Coder Review: 
Not done
Coder Upgrade: 
Not done
Other: 
Other updates done