Php version upgrade from 7.2 to 7.4 in ubuntu 18.04

Hi Team,
I have an Ubuntu server where ISPConfig and WordPress are operating. I need to update the PHP version on the Ubuntu server.
The following are some questions:
1.Shall I update PHP from 7.2 to 7.4 on Ubuntu 18.04?
2.Is it necessary to update ISPConfig while updating PHP?
3.Ubuntu 18.04 supports the PHP version 7.4
4.What are the prerequisites that must be met before updating?
5.What are the expected consequences of updating PHP?
6.If it does not work, How to Implement a backout Plan with No Downtime

Please assist me in moving on without issue.

 

You don't have to upgrade PHP version, you have to install multiphp versions:
https://www.howtoforge.com/ispconfig-php-ubuntu/
If you have WordPress updated, it should be better PHP 8 instead of 7.4

 

ISPConfig supports multiple php versions as mentioned above for app or web sites in it but for the server itself it only supports default php shipped with that OS version.

 

also, to point out what's not been said yet.. you need to either update that server to 20.04, or better, 22.04 (or migrate sites/services to a new server/vps with the newer OS release)
or subscribe to ubuntu pro. otherwise you'll no longer receive OS updates after the end of this month.

 

After updating PHP version from 7.4 to 8.0 on ubuntu 20.04 unable to process ISPConfig console page and added PHP version on ISPConfig.
After changing PHP version default to 7.4 then it unable to load the page

Please find the below error log when i trying to run a script /usr/local/ispconfig/server/server.sh:

WARNING - There is already a lockfile set, but no process running with this pid (2652601). Continuing.
PHP Warning: Undefined array key "admin_mail" in /usr/local/ispconfig/server/server.php on line 97
PHP Warning: Undefined array key "template" in /usr/local/ispconfig/server/lib/classes/tpl_ini.inc.php on line 92
PHP Warning: Trying to access array offset on value of type null in /usr/local/ispconfig/server/lib/classes/tpl_ini.inc.php on line 92
PHP Warning: Undefined array key "template" in /usr/local/ispconfig/server/lib/classes/tpl_ini.inc.php on line 92
PHP Warning: Trying to access array offset on value of type null in /usr/local/ispconfig/server/lib/classes/tpl_ini.inc.php on line 92
PHP Warning: Undefined array key "template" in /usr/local/ispconfig/server/lib/classes/tpl_ini.inc.php on line 92
PHP Warning: Trying to access array offset on value of type null in /usr/local/ispconfig/server/lib/classes/tpl_ini.inc.php on line 92
PHP Warning: Undefined array key "template" in /usr/local/ispconfig/server/lib/classes/tpl_ini.inc.php on line 92
PHP Warning: Trying to access array offset on value of type null in /usr/local/ispconfig/server/lib/classes/tpl_ini.inc.php on line 92
PHP Fatal error: Uncaught TypeError: count(): Argument #1 ($value) must be of type Countable|array, null given in /usr/local/ispconfig/server/lib/classes/tpl.inc.php(1344) : eval()'d code:621
Stack trace:
#0 /usr/local/ispconfig/server/lib/classes/tpl.inc.php(1344): eval()
#1 /usr/local/ispconfig/server/lib/classes/tpl.inc.php(788): tpl->_parse()
#2 /usr/local/ispconfig/server/plugins-available/apache2_plugin.inc.php(1904): tpl->grab()
#3 /usr/local/ispconfig/server/lib/classes/plugins.inc.php(120): apache2_plugin->update()
#4 /usr/local/ispconfig/server/mods-available/web_module.inc.php(137): plugins->raiseEvent()
#5 /usr/local/ispconfig/server/lib/classes/modules.inc.php(302): web_module->process()
#6 /usr/local/ispconfig/server/lib/classes/modules.inc.php(235): modules->raiseTableHook()
#7 /usr/local/ispconfig/server/server.php(180): modules->processDatalog()
#8 {main}
thrown in /usr/local/ispconfig/server/lib/classes/tpl.inc.php(1344) : eval()'d code on line 621

Also, I have attached the screenshot of ISPConfig console page.

 

Everyone in this thread told you not to upgrade the default PHP version of the system.

Code:

sudo update-alternatives --set php /usr/bin/php7.4
sudo update-alternatives --set phar /usr/bin/phar7.4
sudo update-alternatives --set phar.phar /usr/bin/phar.phar7.4

sudo update-alternatives --config php
# Select the php7.4

sudo update-alternatives --config phar
# Select the php7.4

sudo update-alternatives --config phar.phar
# Select the php7.4


sudo a2dismod php8.0
sudo a2enmod php7.4
sudo systemctl restart apache2

This should be enough to get the deafult PHP version back to 7.4. Try if the panel works correctly afterwards. May consider rebooting in between.

 

Hello Pyte,
It worked after I made the changes you recommended in the discussion.
I'm able to access ISPConfig console page.

Thanks for your support.