Ubuntu – How to enable PHP 7.3 in Apache2

php and php-curl are now working.

What led me to the answer is noticing a difference between php7.0.conf and php7.2.conf in /etc/apache2/mods-available/, that would only affect how php performed within the userdir. I then checked whether php worked at the server and saw that it did.

In summary, I believe that after the update from ubuntu 16.04 and 18.04 I needed to

• disable php7.0 and enable php7.2: this created a problem with the user directory php scripts, but did fix the php-curl under the server. In other words, at this point php an php-curl was functioning at the server address;
• edit the php7.2.conf file and comment out the <IfModule mod_userdir.c> section;
• for those reading the entire question, I did not keep the edit to the php.ini file;
• cleared the cache from firefox: the change did not fix the userdir problem until I did the following: open menu->preferences->privacy and security->history->use custom settings for history->clear history->settings->history->cache (all other boxes unchecked)

php and php-curl now working in userdir.

Thanks to everyone who left a comment.

1. Install dependencies.

   Ubuntu 16.04:

   sudo apt install autoconf automake bison build-essential curl flex \
     libtool libssl-dev libcurl4-openssl-dev libxml2-dev libreadline7 \
     libreadline-dev libsqlite3-dev libzip-dev libzip4 nginx openssl \
     pkg-config re2c sqlite3 zlib1g-dev libonig2 libonig-dev
   

   Ubuntu 18.04

   sudo apt install autoconf automake bison build-essential curl flex \
     libtool libssl-dev libcurl4-openssl-dev libxml2-dev libreadline7 \
     libreadline-dev libsqlite3-dev libzip-dev libzip4 nginx openssl \
     pkg-config re2c sqlite3 zlib1g-dev libonig4 libonig-dev
   

   Ubuntu 20.04

   sudo apt install autoconf automake bison build-essential curl flex \
     libtool libssl-dev libcurl4-openssl-dev libxml2-dev libreadline8 \
     libreadline-dev libsqlite3-dev libzip-dev libzip5 nginx openssl \
     pkg-config re2c sqlite3 zlib1g-dev libonig5 libonig-dev
   

   So you don't overwrite any existing PHP installs on your system, install PHP in your home directory. Create a directory for the PHP binaries.

    mkdir -p ~/bin/php7-latest/
   

2. Download the PHP 7.3 from GitHub, decompress it, then change directories using cd to the new directory. You can also download PHP 7.3 from php.net/downloads.php and the installation instructions are exactly the same. Ordinarily this would be the preferred way of downloading PHP 7.3, but I'm using PHP 7.3 from https://github.com/php/ in this answer instead in order to match the PHP 7.3 archive that is asked about in the question.

3. Configure PHP. Remove any options you don't need (like MySQL or Postgres (--with-pdo-pgsql))

    ./configure --prefix=$HOME/bin/php-latest \
        --enable-mysqlnd \
        --with-pdo-mysql \
        --with-pdo-mysql=mysqlnd \
        --with-pdo-pgsql=/usr/bin/pg_config \
        --enable-bcmath \
        --enable-fpm \
        --with-fpm-user=www-data \
        --with-fpm-group=www-data \
        --enable-mbstring \
        --enable-phpdbg \
        --enable-shmop \
        --enable-sockets \
        --enable-sysvmsg \
        --enable-sysvsem \
        --enable-sysvshm \
        --enable-zip \
        --with-libzip=/usr/lib/x86_64-linux-gnu \
        --with-zlib \
        --with-curl \
        --with-pear \
        --with-openssl \
        --enable-pcntl \
        --with-readline
   

   Probably you won't need to remove any of the options except for --with-pdo-pgsql=/usr/bin/pg_config if PostgreSQL isn't installed. If you don't remove an option that is specific to a package that isn't installed, then this command will return an error message that tells you what option must be removed so that the command will run successfully.

4. Compile the binaries:

   make # wait until make is finished
   

   When make is finished you will see the following message:

   Build complete.
   Don't forget to run 'make test'.
   

   Warning: make test takes a long time to finish, so don't run it when the computer is busy.

   make install
   

5. Copy the PHP.ini file to the install directory

   cp php.ini-development ~/bin/php-latest/lib/
   

6. Rename two files.

   cd ~/bin/php-latest/etc/  
   mv php-fpm.conf.default php-fpm.conf
   mv php-fpm.d/www.conf.default php-fpm.d/www.conf
   

7. Create symbolic links for your for your binary file.

   cd ~/bin
   ln -s php-latest/bin/php php
   ln -s php-latest/bin/php-cgi php-cgi
   ln -s php-latest/bin/php-config php-config
   ln -s php-latest/bin/phpize phpize
   ln -s php-latest/bin/phar.phar phar
   ln -s php-latest/bin/pear pear
   ln -s php-latest/bin/phpdbg phpdbg
   ln -s php-latest/sbin/php-fpm php-fpm
   

8. Link your local PHP to the php command. You will need to logout then log back in for php to switch to the local version instead of the installed version from the default Ubuntu repositories.

   # add this to .bashrc
   if [ -d "$HOME/bin" ] ; then
     PATH="$HOME/bin:$PATH"
   fi
   

9. Start PHP-FPM

   sudo ~/bin/php-latest/sbin/php-fpm  
   

   If you run the above command as normal user without sudo, it will show the following notices:

   NOTICE: [pool www] 'user' directive is ignored when FPM is not running as root.    
   NOTICE: [pool www] 'group' directive is ignored when FPM is not running as root.    
   

_{Source: The Install file in php-src-master directory from https://github.com/php/php-src.git contains a link to https://php.net/install from which source these instructions were revised. In addition to several small revisions I added information about how to install PHP 7.3 locally in your home directory without requiring root permissions.}