Warning: Illegal string offset ‘gpage_id’ FIX

Quick fix for everybody that has issue with warning: Illegal string offset ‘gpage_id’ etc.

Change following rows in core/loader.php

115 $order = groups_get_groupmeta( $bp->groups->current_group->id, 'bpge_nav_order' );

to

115 $order = (array) groups_get_groupmeta( $bp->groups->current_group->id, 'bpge_nav_order' );

and

1077 $old_data = groups_get_groupmeta( $bp->groups->current_group->id, 'bpge' );

to

1077 $old_data = (array) groups_get_groupmeta( $bp->groups->current_group->id, 'bpge' );;

That worked for me with PHP 7.3