Fatal error: Call to undefined method PEAR::getVersion() in /usr/share/php/PEAR.php on line 218

[Gijs Hillenius]

Hi there

Simple user here, trying to install this on a raspberry.

Here is the relevant bit from the Virtual host in the apache2 conf.

,----
|         ServerName testing.hillenius.net
|         ServerAdmin webmaster@localhost
|         DocumentRoot /var/www/gnu-social/public
|         <Directory /var/www/gnu-social/public>
|                 AllowOverride All
|                 Order Deny,Allow
|                 Allow from all
|         </Directory>
`----

please note: this address is (for now) only on the lan.

With the above, I reach the install script here:
testing.hillenius.net/install.php

I've fill in all values, and hit Submit. I then get:

,----
| Install GNU social
| 
| Page notice
| 
|         Initializing...
|         Starting installation...
|         Checking database...
|         Creating database tables...
| 
|         Fatal error: Call to undefined method PEAR::getVersion() in 
/usr/share/php/PEAR.php on line 218
`----

Installed PHP packages (from Pi OS Debian 'testing')

libapache2-mod-php7.4 libmarkdown-php php php-auth-sasl php-cli
php-common php-curl php-date php-db php-fpm php-gd php-http-request2
php-intl php-json php-ldap php-mail php-mail-mime php-mbstring php-mysql
php-net-ldap2 php-net-smtp php-net-socket php-net-url2 php-pear
php-stomp php-validate php-xml php7.4 php7.4-bcmath php7.4-cli
php7.4-common php7.4-curl php7.4-fpm php7.4-gd php7.4-gmp php7.4-intl
php7.4-json php7.4-ldap php7.4-mbstring php7.4-mysql php7.4-opcache
php7.4-readline php7.4-xml

I would appreciate pointers. In return, I can offer assistance with
documentation, for example on how to get gnu-social-master.tar.gz
running on Debian testing.

Kind greetings

Gijs