apache2 changing from mpm_prefork to mpm_event

[Jarosław Kłopotek - INTERDUO <jkl@interduo.pl>]

I've got apache2 with mpm_prefork. I would like to change that to 
mpm_event so I do:

root@ht2:~# a2dismod mpm_prefork
ERROR: The following modules depend on mpm_prefork and need to be 
disabled first: php7.2

That's ok I will disable this module also temporary.

root@ht2:~# a2dismod php7.2 mpm_prefork
Module php7.2 disabled.
Module mpm_prefork disabled.
To activate the new configuration, you need to run:
  systemctl restart apache2

And then try to enable back:

root@ht2:~# a2enmod mpm_event
Considering conflict mpm_worker for mpm_event:
Considering conflict mpm_prefork for mpm_event:
Enabling module mpm_event.
To activate the new configuration, you need to run:
  systemctl restart apache2

root@ht2:~# a2enmod php7.2
Considering dependency mpm_prefork for php7.2:
Considering conflict mpm_event for mpm_prefork:
ERROR: Module mpm_event is enabled - cannot proceed due to conflicts. It 
needs to be disabled first!
Considering conflict mpm_worker for mpm_prefork:
ERROR: Could not enable dependency mpm_prefork for php7.2, aborting

This is something wrong. Apache2 should check if one of the installed 
mpm's is enabled not just only to check if mpm_prefork is enabled.

Do You know any workaround?

Regards

--
Jarosław Kłopotek
kom. 607 893 111
Interduo Ł. Bujek, J. Kłopotek, J. Sowa s.c.
ul. Lubelska 36B/40, 21-100 Lubartów
tel. 81 475 30 00