Application broken after upgrading from v4.03 to v4.0.4

It was in the change log:

Added $arguments parameter to after() and before() in FilterInterface. This is a breaking change, so all code implementing the FilterInterface must be updated

In the update the following error occurred:
Fatal error: Uncaught Error: Call to undefined function CodeIgniter \ locale_set_default () in C: \ wwwroot \ system \ CodeIgniter.php: 184 Stack trace: # 0 C: \ wwwroot \ system \ bootstrap.php (181): CodeIgniter \ CodeIgniter -> initialize () # 1 C: \ wwwroot \ index.php (36): require ('C: \\ wwwroot \\ syst ...') # 2 {main} thrown in C: \ wwwroot \ system \ CodeIgniter .php online 184
The line was commented and the problem solved:

//locale_set_default ($ this-> config-> defaultLocale ?? 'en');