一、卸载php7.2

yum remove php*

需要将centos的yum源更新
二、源报错问题或者yum源不是最新请执行一下命令

Error: Failed to download metadata for repo ‘appstream’: Cannot prepare interna

#进入yum源目录cd /etc/yum.repos.d替换yum配置sed -i 's/mirrorlist/#mirrorlist/g' /etc/yum.repos.d/CentOS-*sed -i 's|#baseurl=http://mirror.centos.org|baseurl=http://vault.centos.org|g' /etc/yum.repos.d/CentOS-*#备份yum配置mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo_bak#下载最新yum配置wget -O /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-vault-8.5.2111.repo

三、安装remi存储库

dnf install https://rpms.remirepo.net/enterprise/remi-release-8.rpm

若报错：

Error:
 Problem: conflicting requests
  - nothing provides redhat-release >= 8.6 needed by remi-release-8.6-1.el8.remi.noarch
(try to add '--skip-broken' to skip uninstallable packages or '--nobest' to use not only best candidate packages)

解决：

rpm -Uvh http://rpms.famillecollet.com/enterprise/remi-release-8.rpmwget http://rpms.famillecollet.com/enterprise/remi-release-8.rpmrpm -ivh remi-release-8.rpm

四、安装EPEL存储库

dnf install https://dl.fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpm

五、安装好EPEL和Remi存储库后，执行以下命令以获取可用PHP模块流的列表

dnf module list php

[e]nabled, [x]disabled, [i]nstalled

如果没有php74更新下源库

dnf update

dnf makecache

六、启用php74模块流

dnf module reset phpdnf module enable php:remi-7.4

七、安装php74

dnf install php php-cli php-commonphp -v

来源地址：https://blog.csdn.net/kingsoulfat/article/details/127845702