Latest PHP version

• adding PPA: sudo add-apt-repository ppa:ondrej/php -y; sudo apt-get update
• removing current version: sudo apt-get purge php* php*-fpm && sudo apt-get --purge autoremove
• installing latest version (replace X with the latest version, eg 7.3): PHP_VERSION='X'; sudo apt-get install php$PHP_VERSION php$PHP_VERSION-curl php$PHP_VERSION-intl php$PHP_VERSION-pgsql php$PHP_VERSION-json php$PHP_VERSION-mbstring php$PHP_VERSION-zip php$PHP_VERSION-xml php$PHP_VERSION-fom apache2- apache2-bin- Settings that usually need to be overwritten in /etc/php/$PHP_VERSION/*/conf.d/99-custom.ini:

; For security reason
expose_php = Off
display_errors = Off
allow_url_include = Off
session.cookie_httponly = 1
session.use_strict_mode = 1
session.cookie_secure = 1
session.cookie_samesite = Strict
session.use_trans_sid = 0
session.sid_length = 128
session.sid_bits_per_character = 6

; For \date() and \DateTime()
date.timezone = UTC

; For file upload
upload_max_filesize = 21M
post_max_size = 25M

; For performance
opcache.enable=1
opcache.enable_cli=1

Additional settings for PHP-FPM:

; For performance
pm = dynamic
pm.max_children = 8
pm.start_servers = 2
pm.min_spare_servers = 1
pm.max_spare_servers = 3

References: how to properly and securely configure the entire php.ini