How to install intl 55.1 version matched with symfony3?

Question

I have installed symfony 3.1.
An error info occur when to check whether is ready to run Symfony applications.
My intl icu was installed with command apt-get install php5-intl,the version is 52.1 lower than 55.1.

Here is my steps to compile intl icu 55.1 version.
1.download
http://site.icu-project.org/download/55#TOC-ICU4C-Download 2.extract
3.cd ~/Downloads/icu/source
4./configure
5.make
6.make install
7.vim /etc/php5/apache2/php.ini
to add a line : extension=intl.so
8.service apache2 restart 9.cd /home/my_project_name
10.php app/console server:run
11.to check config
to input http://localhost:8000/config.php in firefox

Intl icu55.5 version have be compiled and installed ,why Install and enable the intl extension (used for validators)?
How to fix it?