how to upgrade from php 7.4 to 8.* in ubuntu 20.04 code example

Example 1: upgrade php to 7.3 ubuntu

sudo apt-get install software-properties-common
sudo add-apt-repository ppa:ondrej/php
sudo apt-get update
sudo apt-get upgrade
sudo apt-get install -y php7.3

Example 2: ubuntu 16 upgrade php 7.0 to 7.4

sudo apt install -y php7.4-mysql php7.4-dom php7.4-simplexml php7.4-ssh2 php7.4-xml php7.4-xmlreader php7.4-curl  php7.4-exif  php7.4-ftp php7.4-gd  php7.4-iconv php7.4-imagick php7.4-json  php7.4-mbstring php7.4-posix php7.4-sockets php7.4-tokenizer

Example 3: ubuntu upgrade php to 7.3

sudo apt-get install software-properties-common
sudo add-apt-repository ppa:ondrej/php
sudo apt-get update
sudo apt-get upgrade
sudo apt-get install -y php7.3

Example 4: ubuntu 16 upgrade php 7.0 to 7.4

sudo apt-add-repository ppa:ondrej/php