Symfony2 Form localization now depends on Symfony/Intl and Symfony/Icu components. If the server you run you application has ICU lib version lower than 4.0 you must use the Symfony/Icu 1.0.x component which emulates the ICU lib.
The problem is that it only has support for en locale. My project needs a few more. How could i extend or add support for more locales into Symfony/Icu 1.0.x?