How to downgrade or install a specific version of Composer?

Assuming a regular composer installation, to rollback to version 1 of composer, you simply execute:

composer self-update --1

When you want to go back to version 2 (which you should, after updating or removing the incompatible plugins):

composer self-update --2

The above will take you to the latest on any of the two major versions.

You can also "update" to a specific version just by passing the version number to self-update:

composer self-update 1.10.12composer self-update 2.0.7

And finally after performing any self-update, you can specify --rollback to go back to the previously installed version.

composer self-updatecomposer self-update --rollback

Finally, if you are feeling adventurous, you can update to a pre-release version by executing:

composer self-update --preview

if you have already installed composer on your system. then paste the below code to downgrade the composer version with a specific version as per your need.

composer self-update 1.10.14

for ubuntu system use the below command

sudo -H composer self-update 1.10.14

Just two commands worked for me. Currently I have composer 2.x.x , I had 1.10.x . First one command will download downgrade version and then second command will rollback to 1.x.x

1. php composer self-update --1
2. composer self-update --rollback