Steps to reproduce the issue

I switched today our Joomla 3.10.11 from PHP 7.4 to PHP 8.0.
Error message: count(): Argument #1 ($value) must be of type Countable|array, bool given

Expected result

working page

Actual result

Error message: count(): Argument #1 ($value) must be of type Countable|array, bool given

System information (as much as possible)

Joomla 3.10.11, PHP 8.0

Additional comments

Fixes - after applying them all works fine:

• plugins\system\stools\core\class.helper.php:
  • line 301: $modCnt = count($mods); ---> $modCnt = count((array)$mods);
  • line 399: $max = count((array)$activeMod); ---> $max = count((array)$activeMod);
• modules\mod_ju_msilders\mod_ju_msilders.php:
  • line 12: $path=$_SERVER['HTTP_HOST'].$_SERVER[REQUEST_URI]; ---> $path=$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI'];