how to update composer

Looking at composer I first wanted to check the current version, which is actioned by running the following command

composer -V

The response I was seeing

Composer version 2.1.5 2021-07-23 10:35:47

How to update to the latest version of Composer?

Going to the Composer site, today the latest version is 2.5.1.  To update my version to this I need to run

composer self-update

However, if you have the following response

  [Composer\Downloader\FilesystemException]
  Filesystem exception:
  Composer update failed: "/usr/local/bin/composer" could not be written.
  rename(/home/fdrc_drupal_dev/.cache/composer/composer-temp.phar,/usr/local/
  bin/composer): Permission denied

Check the owner permissions that have been set at /usr/local/bin/composer.  If root, then you will need to  run the command as

sudo composer self-update

Subsequent response

Upgrading to version 2.5.1 (stable channel).

Use composer self-update --rollback to return to version 2.1.5

Finally confirming the Composer version using composer -V is giving the response

Composer version 2.5.1 2022-12-22 15:33:54