PHP 7.3 & 7.4 Unable to locate package error

Hi,
Using ISP Config 3 on Ubuntu 18.04.5 LTS
trying to add php 7.3 & 7.4 as additional version by following this tutorial https://www.howtoforge.com/tutorial...fig-3-from-debian-packages-on-debian-8-and-9/
when i run this command;

Code:

apt-get install php7.3 php7.3-cli php7.3-cgi php7.3-fpm php7.3-gd php7.3-mysql php7.3-imap php7.3-curl php7.3-intl php7.3-pspell php7.3-recode php7.3-sqlite3 php7.3-tidy php7.3-xmlrpc php7.3-xsl php7.3-zip php7.3-mbstring php7.3-soap php7.3-opcache php7.3-common php7.3-json php7.3-readline php7.3-xml

server returns;

Code:

Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package php7.3
E: Couldn't find any package by glob 'php7.3'
E: Couldn't find any package by regex 'php7.3'
E: Unable to locate package php7.3-cli
E: Couldn't find any package by glob 'php7.3-cli'
E: Couldn't find any package by regex 'php7.3-cli'
E: Unable to locate package php7.3-cgi
E: Couldn't find any package by glob 'php7.3-cgi'
E: Couldn't find any package by regex 'php7.3-cgi'
E: Unable to locate package php7.3-fpm
E: Couldn't find any package by glob 'php7.3-fpm'
E: Couldn't find any package by regex 'php7.3-fpm'
E: Unable to locate package php7.3-gd
E: Couldn't find any package by glob 'php7.3-gd'
E: Couldn't find any package by regex 'php7.3-gd'
E: Unable to locate package php7.3-mysql
E: Couldn't find any package by glob 'php7.3-mysql'
E: Couldn't find any package by regex 'php7.3-mysql'
E: Unable to locate package php7.3-imap
E: Couldn't find any package by glob 'php7.3-imap'
E: Couldn't find any package by regex 'php7.3-imap'
E: Unable to locate package php7.3-curl
E: Couldn't find any package by glob 'php7.3-curl'
E: Couldn't find any package by regex 'php7.3-curl'
E: Unable to locate package php7.3-intl
E: Couldn't find any package by glob 'php7.3-intl'
E: Couldn't find any package by regex 'php7.3-intl'
E: Unable to locate package php7.3-pspell
E: Couldn't find any package by glob 'php7.3-pspell'
E: Couldn't find any package by regex 'php7.3-pspell'
E: Unable to locate package php7.3-recode
E: Couldn't find any package by glob 'php7.3-recode'
E: Couldn't find any package by regex 'php7.3-recode'
E: Unable to locate package php7.3-sqlite3
E: Couldn't find any package by glob 'php7.3-sqlite3'
E: Couldn't find any package by regex 'php7.3-sqlite3'
E: Unable to locate package php7.3-tidy
E: Couldn't find any package by glob 'php7.3-tidy'
E: Couldn't find any package by regex 'php7.3-tidy'
E: Unable to locate package php7.3-xmlrpc
E: Couldn't find any package by glob 'php7.3-xmlrpc'
E: Couldn't find any package by regex 'php7.3-xmlrpc'
E: Unable to locate package php7.3-xsl
E: Couldn't find any package by glob 'php7.3-xsl'
E: Couldn't find any package by regex 'php7.3-xsl'
E: Unable to locate package php7.3-zip
E: Couldn't find any package by glob 'php7.3-zip'
E: Couldn't find any package by regex 'php7.3-zip'
E: Unable to locate package php7.3-mbstring
E: Couldn't find any package by glob 'php7.3-mbstring'
E: Couldn't find any package by regex 'php7.3-mbstring'
E: Unable to locate package php7.3-soap
E: Couldn't find any package by glob 'php7.3-soap'
E: Couldn't find any package by regex 'php7.3-soap'
E: Unable to locate package php7.3-opcache
E: Couldn't find any package by glob 'php7.3-opcache'
E: Couldn't find any package by regex 'php7.3-opcache'
E: Unable to locate package php7.3-common
E: Couldn't find any package by glob 'php7.3-common'
E: Couldn't find any package by regex 'php7.3-common'
E: Unable to locate package php7.3-json
E: Couldn't find any package by glob 'php7.3-json'
E: Couldn't find any package by regex 'php7.3-json'
E: Unable to locate package php7.3-readline
E: Couldn't find any package by glob 'php7.3-readline'
E: Couldn't find any package by regex 'php7.3-readline'
E: Unable to locate package php7.3-xml
E: Couldn't find any package by glob 'php7.3-xml'
E: Couldn't find any package by regex 'php7.3-xml'

What am i doing wrong?

 

oh my, i'm rookie on linux systems i thought debian and ubuntu shares same system, sorry.

 

May be it's good to add this into the tutorial as well?