Last update of BackWPUp (5.2.2) crash website with MainWp Child

[freepixelweb (Lagarrigue)]

Hi, I see that all my child websites crach with 5.2.2 BackWPUp update when MainWP Child is activated:

An E_ERROR error was caused on line 141 of file /home/mydomain/wp-content/plugins/mainwp-child/class/class-mainwp-child-back-wp-up.php. Error message: Uncaught Error: Call to undefined method BackWPup::get_instance() in /home/mydomain/wp-content/plugins/mainwp-child/class/class-mainwp-child-back-wp-up.php:141
Stack trace:
#0 /home/mydomain/wp-content/plugins/mainwp-child/class/class-mainwp-child-back-wp-up.php(95): MainWP\Child\MainWP_Child_Back_WP_Up->__construct()
#1 /home/mydomain/wp-content/plugins/mainwp-child/class/class-mainwp-child.php(433): MainWP\Child\MainWP_Child_Back_WP_Up::instance()
#2 /home/mydomain/wp-content/plugins/mainwp-child/class/class-mainwp-child.php(342): MainWP\Child\MainWP_Child->parse_init_extensions()
#3 /home/mydomain/wp-includes/class-wp-hook.php(324): MainWP\Child\MainWP_Child->parse_init()
#4 /home/mydomain/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters()
#5 /home/mydomain/wp-includes/plugin.php(517): WP_Hook->do_action()
#6 /home/mydomain/wp-settings.php(727): do_action()
#7 /home/mydomain/wp-config.php(104): require_once('/home/sc2laje49...')
#8 /home/mydomain/wp-load.php(50): require_once('/home/sc2laje49...')
#9 /home/mydomain/wp-admin/admin.php(35): require_once('/home/sc2laje49...')
#10 /home/mydomain/wp-admin/update-core.php(10): require_once('/home/sc2laje49...')
#11 {hand} 
thrown

[bojan (Bojan Katusic)]

Hey @freepixelweb

Thank you for reporting this to us.

We have identified a compatibility issue with the BackWPup v5.2.2 and MainWP Child plugin.

The BackWPup v5.2.1 is unaffected.

We expect to have a hotfix release later today.

[bojan (Bojan Katusic)]

The fix for this issue was included in the v5.4.0.8 of the MainWP Child plugin released on 20-05-2025.

Thanks again for reporting this to us.