Symfony 2.4 end of maintenance was reached at the end of July. But as migrating to Symfony 2.5 proved to be difficult because of some bugs, we decided to extend the maintenance until September 2014. So, expect a new release of Symfony 2.4 at the end of August and probably a last one at the end of September. After that, Symfony 2.4 will still receive security issue fixes until January 2015.
Symfony 2.5.3 is going to be released later today and it should fix all problems with the migration from 2.4. If not, please open a ticket and explain the problem so that we can work on a fix as soon as possible.
Thanks for your support.