I manage an old Wordpress Multisite Network (there are 5 sites) and I want to update WP core (from 6.6.2 to 6.7.2), themes and plugins. First step is update obsolete php version 7.3 If I update php from 7.3 to 7.4, the main site detect the new version but other 4 sites detect 7.3. I don't understand where is the problem. The .htaccess file is standard (like WP declares). Somebody can tell me why?

Update: The technician who manages the server says there is a dedicated server with Plesk.

.htaccess:

RewriteEngine On
#RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]
RewriteBase /
RewriteRule ^index\.php$ - [L]

# add a trailing slash to /wp-admin
RewriteRule ^wp-admin$ wp-admin/ [R=301,L]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]
RewriteRule ^(wp-(content|admin|includes).*) $1 [L]
RewriteRule ^(.*\.php)$ $1 [L]
RewriteRule . index.php [L]