Can I do a fresh joomla installation and import the old database, etc from a broken installation?

Question

There's a broken Joomla installation in the host (not made by me) as far as I read, it's because it doesn't work with PHP7+.

I'd like to make a fresh install and reuse the database that the broken installation is currently using. Can this something work?

I have no experience with Joomla, I'm just trying to fix this. Any other suggestions are welcome.

Part of the log error goes like this:

[24-Jul-2022 08:09:11 America/Chicago] PHP Warning:  Version warning: Imagick was compiled against Image Magick version 1650 but version 1654 is loaded. Imagick will run but may behave surprisingly in Unknown on line 0
[24-Jul-2022 08:29:46 America/Chicago] PHP Warning:  Version warning: Imagick was compiled against Image Magick version 1650 but version 1654 is loaded. Imagick will run but may behave surprisingly in Unknown on line 0
[24-Jul-2022 10:23:17 America/Chicago] PHP Warning:  Version warning: Imagick was compiled against Image Magick version 1650 but version 1654 is loaded. Imagick will run but may behave surprisingly in Unknown on line 0
[24-Jul-2022 10:24:11 America/Chicago] PHP Warning:  Version warning: Imagick was compiled against Image Magick version 1650 but version 1654 is loaded. Imagick will run but may behave surprisingly in Unknown on line 0
[24-Jul-2022 10:42:23 America/Chicago] PHP Warning:  Version warning: Imagick was compiled against Image Magick version 1650 but version 1654 is loaded. Imagick will run but may behave surprisingly in Unknown on line 0
[24-Jul-2022 11:24:11 America/Chicago] PHP Warning:  Version warning: Imagick was compiled against Image Magick version 1650 but version 1654 is loaded. Imagick will run but may behave surprisingly in Unknown on line 0
[24-Jul-2022 11:24:16 America/Chicago] PHP Warning:  Version warning: Imagick was compiled against Image Magick version 1650 but version 1654 is loaded. Imagick will run but may behave surprisingly in Unknown on line 0
[24-Jul-2022 11:24:16 America/Chicago] PHP Warning:  Version warning: Imagick was compiled against Image Magick version 1650 but version 1654 is loaded. Imagick will run but may behave surprisingly in Unknown on line 0
[24-Jul-2022 14:54:34 America/Chicago] PHP Warning:  Version warning: Imagick was compiled against Image Magick version 1650 but version 1654 is loaded. Imagick will run but may behave surprisingly in Unknown on line 0
[24-Jul-2022 15:46:42 America/Chicago] PHP Warning:  Version warning: Imagick was compiled against Image Magick version 1650 but version 1654 is loaded. Imagick will run but may behave surprisingly in Unknown on line 0
[24-Jul-2022 18:50:16 America/Chicago] PHP Warning:  Version warning: Imagick was compiled against Image Magick version 1650 but version 1654 is loaded. Imagick will run but may behave surprisingly in Unknown on line 0
[24-Jul-2022 19:45:00 America/Chicago] PHP Warning:  Version warning: Imagick was compiled against Image Magick version 1650 but version 1654 is loaded. Imagick will run but may behave surprisingly in Unknown on line 0
[24-Jul-2022 20:11:38 America/Chicago] PHP Warning:  Version warning: Imagick was compiled against Image Magick version 1650 but version 1654 is loaded. Imagick will run but may behave surprisingly in Unknown on line 0
[24-Jul-2022 20:30:40 America/Chicago] PHP Warning:  Version warning: Imagick was compiled against Image Magick version 1650 but version 1654 is loaded. Imagick will run but may behave surprisingly in Unknown on line 0
[18-Oct-2022 13:25:43 America/Chicago] PHP Fatal error:  Uncaught Error: Call to undefined function set_magic_quotes_runtime() in /home1/pegasena/public_html/old/joomla_site/includes/framework.php:21
Stack trace:
#0 /home1/pegasena/public_html/old/joomla_site/index.php(22): require_once()
#1 {main}
  thrown in /home1/pegasena/public_html/old/joomla_site/includes/framework.php on line 21
[18-Oct-2022 13:25:46 America/Chicago] PHP Fatal error:  Uncaught Error: Call to undefined function set_magic_quotes_runtime() in /home1/pegasena/public_html/old/joomla_site/includes/framework.php:21
Stack trace:
#0 /home1/pegasena/public_html/old/joomla_site/index.php(22): require_once()
#1 {main}
  thrown in /home1/pegasena/public_html/old/joomla_site/includes/framework.php on line 21
[18-Oct-2022 13:34:47 America/Chicago] PHP Fatal error:  Uncaught Error: Call to undefined function set_magic_quotes_runtime() in /home1/pegasena/public_html/old/joomla_site/includes/framework.php:21
Stack trace:
#0 /home1/pegasena/public_html/old/joomla_site/index.php(22): require_once()
#1 {main}
  thrown in /home1/pegasena/public_html/old/joomla_site/includes/framework.php on line 21
[19-Oct-2022 12:40:44 America/Chicago] PHP Fatal error:  Uncaught Error: Call to undefined function set_magic_quotes_runtime() in /home1/pegasena/public_html/old/joomla_site/includes/framework.php:21
Stack trace:
#0 /home1/pegasena/public_html/old/joomla_site/index.php(22): require_once()
#1 {main}
  thrown in /home1/pegasena/public_html/old/joomla_site/includes/framework.php on line 21

Answer 1

The PHP function set_magic_quotes_runtime that is visible in your error message has been DEPRECATED as of PHP 7.4.0, and REMOVED as of PHP 8.0.0, see https://www.php.net/manual/en/function.get-magic-quotes-runtime.php

The Joomla documentation has some info about upgrading: https://docs.joomla.org/Portal:Upgrading_Versions

Answer 2

You may be able to add a directive to the .htaccess file in the root folder of the website to set the PHP version back to 5.6 or similar e.g.:

AddHandler application/x-httpd-php56 .php .php5

Alternatively, the files and database could be backed up and restored to an alternative host running an older version of PHP.

Once the website is on a compatible version of PHP, you can then upgrade third party extensions and Joomla so they are compatible with PHP 7.