Can you also check not only in CLI env but also in WEB? By creating simple file with
<?php phpinfo(); and running it on browser?
You're right, the "apache2" php doesn't know about the phalcon module. phpinfo doesn't show the module.
The phpinfo produced by the cli shows the module
php -r "phpinfo();"
Web framework delivered as a C-extension for PHP
phalcon => enabled
Author => Phalcon Team and contributors
Version => 3.4.5
Build Date => Oct 30 2019 16:08:08
Powered by Zephir => Version 0.10.16-6826149172
It's not a version problem, it's a global (apache) phalcon install problem.
I insist, I only did an apt upgrade.
I'll investigate further, if you have another hint for me, you're very welcome.