為了使用 Codeignitor4 ，不得已把php升到7.4 ，參考資料[1]的作法，他採用直接升級的方法，無痛而且簡單。
目前環境
CentOS Linux release 8.3.2011
PHP 7.2.24
安裝repository
# dnf -y install https://dl.fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpm
# dnf install -y http://rpms.remirepo.net/enterprise/remi-release-8.rpm
# dnf install -y http://rpms.remirepo.net/enterprise/remi-release-8.rpm
以上dnf如果沒有的話使用yum亦可
安裝 php 7.4版
# sudo dnf module install php:remi-7.4
Last metadata expiration check: 1:40:17 ago on Wed 05 May 2021 10:44:55 AM CST.
Dependencies resolved.
The operation would result in switching of module 'php' stream '7.2' to stream 'remi-7.4'
Error: It is not possible to switch enabled streams of a module.
It is recommended to remove all installed content from the module, and reset the module using 'dnf module reset <module_name>' command. After you reset the module, you can install the other stream.
Last metadata expiration check: 1:40:17 ago on Wed 05 May 2021 10:44:55 AM CST.
Dependencies resolved.
The operation would result in switching of module 'php' stream '7.2' to stream 'remi-7.4'
Error: It is not possible to switch enabled streams of a module.
It is recommended to remove all installed content from the module, and reset the module using 'dnf module reset <module_name>' command. After you reset the module, you can install the other stream.
報錯，把 module reset掉重試
# sudo dnf module reset php
# sudo dnf module install php:remi-7.4
進入安裝/升級程序，版本檢查
# php -v
PHP 7.4.19 (cli) (built: May 4 2021 11:06:37) ( NTS )
Copyright (c) The PHP Group
Zend Engine v3.4.0, Copyright (c) Zend Technologies
with Zend OPcache v7.4.19, Copyright (c), by Zend Technologies
PHP 7.4.19 (cli) (built: May 4 2021 11:06:37) ( NTS )
Copyright (c) The PHP Group
Zend Engine v3.4.0, Copyright (c) Zend Technologies
with Zend OPcache v7.4.19, Copyright (c), by Zend Technologies
簡單容易。