Get list of outdated packages

I want to get list of outdated packages that will be updated when I issue composer update. Does composer have such functionality? if no is there a way to do that (with or without composer?)

Update:

Since Composer v1.1 (May 2016) the following commands are available:

• composer outdated shows you the list of outdated packages
• composer show -l returns the complete list of packages. packages in need of update are colored red. the (still) up-2-date ones are colored green.
• both commands accept the parameter --direct to show only direct dependencies in the listing

Referencing:

https://github.com/composer/composer/issues/3771

Composer Plugins

There are some Composer Plugins showing the list of outdated packages:

1. composer-versions-check - https://github.com/Soullivaneuh/composer-versions-check

   The Composer Plugin called "composer-versions-check" shows outdated packages from last major versions after using the update command. (Latest is ..)

   This plugin runs "update" first, then shows possible "upgrade" indications.

   A Composer dry-run isn't supported, yet.

   

2. vinkla/climb - https://github.com/vinkla/climb

   Climb is a "Composer version manager tool" inspired by npm-check-updates.

   It shows the outdates package version and indicates "upgrades" to latest versions.

Since version 1.1 of Composer there is the composer outdated command. With composer outdated --direct only your direct dependencies are taken into account.