How to get rid of intl deprecation message with symfony 5

Question

Since I updated my project from symfony 4.4 to 5.0, I have on all my pages the following deprecation warning (only warning I'm having) :

Please install the "intl" PHP extension for best performance.

After searching for a solution, I thought that I needed to install the intl component, which I did :

composer require symfony/intl

I also installed the symfony/translation component :

composer require symfony/translation

The problem is the deprecation is still here (even after bin/console cache:clear and restarting symfony serve).

If this is a warning, simply ignore it. Otherwise, why not just follow the recommendation - "best performance" sounds like something worth to achieve? — Nico Haase
The problem with leaving a warning is that you don't pay attention to new warnings => the little orange button isn't that different with "1" or "2" on it. I like to keep the number of warnings to 0 ; it's time consuming during development but it makes me gain time in the end. — Diabetic Nephropathy
Then don't ignore the warning and install the extension, simple as that — Nico Haase
I managed to install it as I said in my comment of the solution answer. And "simple as that" -> depending on configuration, installing intl PHP extension on macOS Catalina isn't as simple as it sounds… (see my other comment for more detail) — Diabetic Nephropathy
Pretty strange. How did you install PHP after all? According to stackoverflow.com/questions/46652968/…, it's as simple as installing PHP through Brew and Intl is activated — Nico Haase

Dmitry Gorbachev Dmitry Gorbachev · Accepted Answer · 2020-10-15T01:50:20

You need to install intl PHP extension instead of Symfony component symfony/intl

See manuals for installation on your OS. For example on Ubuntu/Debian

sudo apt-get install php-intl

Check if extension installed

php -m | grep intl
intl # must be printed this line with extension name