PHP upgrade can break a previously working ActiveCollab because of version incompatibility, as well as extension and runtime configuration changes.
Prior to upgrading PHP, check if your version of ActiveCollab supports it. Check out compatibility table on System Requirements page for details.
Prior and after doing and upgrade, run probe.php script to confirm that environment is working correctly.
This is most probably due to a missing IMAP extension. To check if IMAP extension is installed, please run this command:
php -m | grep imap
If IMAP extension is found, it will be listed. If not, this command will just output a blank line.
It is important to use command line to check if IMAP extension is installed, not phpinfo(). Incoming mail is always imported from cron jobs, and they run in command line environment. phpinfo() displays the configuration of your web environment. It can lead you to an incorrect conclusions, because web and command line environment are different and can be differently configured.
After PHP upgrade you may experience a broken ActiveCollab, and find this error in server responses or in log files: Call to a member function execute() on null in .../activecollab/5.X.Y/angie/classes/database/DB.class.php.
What this error means is that ActiveCollab can't connect to the database, despite having correct connection parameters in config/config.php.
This is usually due to MySQLi extension configuration, which may be disabled or reset to default configuration after you upgraded PHP.
First step is to check if MySQLi extension is installed. You can do that by visiting a phpinfo() page that you made, or by running this command:
php -m | grep mysqli
If MySQLi extension is found, it will be listed. If not, this command will just output a blank line. You can yse php -m to get the list of all enabled extensions.
Next step is to check MySQLi runtime configuration. You can get all settings on phpinfo() page, or by running this command:
php -i | grep mysqli
It will list all lines from PHP runtime configuration that have mention of mysqli. Check if all settings are OK. Pay close attention of default socket option, because it can result in functional MySQLi extension that can't connect to MySQL server. Consult the PHP and MySQL installation guide that you used to set up the environment to see how to correctly set up the mysql.sock.
If you did the full platform refresh, and upgraded both PHP and MySQL in the same go, make sure that all MySQL upgrade steps are completed.
Check the upgrade guide that you followed through, and verify that all steps have been completed. Information about mysql_upgrade command should be part of that guide. If it's not, you can find more information in the official documentation. mysql_upgrade command will check all database tables, and make sure that they are upgraded. It will also refresh system tables that are needed for normal operation of MySQL server.