How to update MB Settings field programatically

Hi guys,

We need to be able to update a MB settings value from within a function. I've previously reached out on Github (https://github.com/wpmetabox/meta-box/issues/1245) but am posting here to in the hope that someone can help asap. We have a client site experiencing issues as our solution (see github post) no longer works.

This is what we were using:

$next_member_number_incremented = $next_member_number + 1;
$rwmb_setting_method = new RWMB_Setting_Storage; // Obviously requires MB Settings Page to work!
$increment_next_member_number = $rwmb_setting_method->update('indigo_membership_settings','member_number_next',$next_member_number_incremented);

But this now returns an error:

Fatal error: Uncaught Error: Class 'RWMB_Setting_Storage' not found in....

Any help gratefully appreciated.

Thanks,

Will