I have a local development site on Ubuntu and currently my system has PHP 7.4 installed and I can see Drupal site using the correct version in terminal using
drush st but if I browse to Admin UI and check the PHP version in status page it is showing different version.
In case it helps Initially the site was setup on PHP 7.2 later on PHP version is updated on the system.
drush @local.local st Drupal version : 8.9.0 Site URI : http://local.d8site.local DB driver : mysql DB hostname : localhost DB port : 3306 DB username : drupal DB name : d8site_local Database : Connected Drupal bootstrap : Successful Default theme : bartik Admin theme : seven PHP binary : /usr/bin/php7.4 PHP config : /etc/php/7.4/cli/php.ini PHP OS : Linux Drush script : /var/www/local.d8site.local/vendor/drush/drush/drush Drush version : 10.2.2 Drush temp : /tmp Drush configs : /var/www/local.d8site.local/vendor/drush/drush/drush .yml /var/www/local.d8site.local/drush/drush.yml Install profile : standard Drupal root : /var/www/local.d8site.local/web Site path : sites/local Files, Public : sites/local/files Files, Temp : /tmp
php --version PHP 7.4.9 (cli) (built: Aug 7 2020 14:29:36) ( NTS ) Copyright (c) The PHP Group Zend Engine v3.4.0, Copyright (c) Zend Technologies with Zend OPcache v7.4.9, Copyright (c), by Zend Technologies with Xdebug v2.9.6, Copyright (c) 2002-2020, by Derick Rethans