Multisite install not working

Hello. I’m a free user but I hope you can direct me in the right way to solve this issue so we can use your plugin.

We have a multisite install.
Installed PMPro + the multisite add-on per instructions on your github page.
I went thru all 6 items on the list.

All seemed fine yesterday, although we were still mid-testing to see if members registered on main site were registered on sub-site too.

This afternoon, however, the whole thing started creating errors.

I had to delete entire plugin and add-ons to start over.
Now I activate main plugin at my main site. All good there.
But as soon as I activate pmpro-network-subsite-dev add-on in my sub-site, I get a critical error on sub-site.

The only way to get my sub-site back is by deleting your plugin + add-ons.

I’m on debug trying to understand what is happening and cant.

Here’s the debug info :

[07-Oct-2020 15:34:05 UTC] PHP Fatal error: Uncaught Error: Call to undefined function pmpro_getAllLevels() in /home/u957978957/domains/mysite.com/public_html/wp-content/plugins/pmpro-network-subsite-dev/pmpro-network-subsite.php:78
Stack trace:
#0 /home/u957978957/domains/mysite.com/public_html/wp-includes/class-wp-hook.php(287): pmpro_multisite_membership_init_get_levels(”)
#1 /home/u957978957/domains/mysite.com/public_html/wp-includes/class-wp-hook.php(311): WP_Hook->apply_filters(NULL, Array)
#2 /home/u957978957/domains/mysite.com/public_html/wp-includes/plugin.php(478): WP_Hook->do_action(Array)
#3 /home/u957978957/domains/mysite.com/public_html/wp-settings.php(546): do_action(‘init’)
#4 /home/u957978957/domains/mysite.com/public_html/wp-config.php(100): require_once(‘/home/u957978957…’)
#5 /home/u957978957/domains/mysite.com/public_html/wp-load.php(37): require_once(‘/home/u957978957…’)
#6 /home/u957978957/domains/mysite.com/public_html/wp-admin/admin.php(34): require_once(‘/home/u957978957…’)
#7 /home/u957978957/domains/mysite.com/public_htm in /home/u957978957/domains/mysite.com/public_html/wp-content/plugins/pmpro-network-subsite-dev/pmpro-network-subsite.php on line 78

I’ve tried deactivating other plugins but it does not seem related to any other plugin.

Suggestions?