Updates all the version constraints of dependencies in the composer.json file to their latest version.

When you install a package using composer require vendor/package, a entry for example "vendor/package": "^1.4" is added to the composer.json file. It means that Composer can update to patch and minor releases: 1.4.1, 1.5.0 and so on. But not to major version, which means, in this example, 2.0 and higher.

To discover new releases of the packages, you run composer outdated. Some of those updates can be major releases. Running composer update won’t update the version of those.

To update to a new major versions, use this tool Composer Frontline.

Install it:

composer global require dg/composer-frontline

then run it:

composer frontline

it will print something like:

vendor/package      ^1.4  →  ^2.0
nette/mail          ^1.0  →  ^3.1
latte/latte         ^1.6  →  ^2.8

This will upgrade all the version hints in the composer.json file, in require and require-dev sections. It only modifies composer.json file. So run composer update to update your packages.

You can also update only specific packages using names and wildcards:

composer frontline  nette/*
composer frontline  doctrine/* symfony/console

Make sure your composer.json file is in version control and all changes have been committed. This will overwrite your composer.json file.