Composer and CLI php version change

 Compoer 

composer self-update --1

CLI php version

sudo update-alternatives --set php /usr/bin/php7.2

Magento 2.4.x install | getting error Invalid credentials for 'xxxproject-community-edition/magento-project-community-edition-2.4.2.0.zip', aborting.

 I am trying to install Magento 2.4.x via composer but it giving below error. Have any one idea. 

Invalid credentials for 'https://repo.magento.com/archives/magento/project-community-edition/magento-project-community-edition-2.4.2.0.zip', aborting.

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How to upgrade or downgrade 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