Use of undefined constant INVITE_SESSION - assumed 'INVITE_SESSION' in user_relationship_invites_form_user_register_form_alter(

invite module is using constant INVITE_SESSION_CODE instead of INVITE_SESSION

Looks like the constant was renamed in 4.x. Maybe this should be fixed as part of the 4.x integration issue?

Berdir you are right this belongs to Invite 4.x

Ok, closing as a duplicate of #2041769: Upgrade user_relationship_invites to work with Invite 4.x branch then.

this all happens on line 106

This is not a duplicate of the other issue.
The constant is defined in the invite module.
The patch fixes the problem

This is not a duplicate of the other issue.
The constant is defined in the invite module.
The patch fixes the problem

@socialnicheguru From what I understand on this issue the sub module in user_relationships is for 3.x, the linked issue that was marked as duplicate is one to update the sub module to 4.x.

Looking at #2041769: Upgrade user_relationship_invites to work with Invite 4.x branch we're not updating the module and a separate project was created for this by @mrded:
https://www.drupal.org/project/invite_user_relationships

should I delete the submodule?
maybe there should be a patch to delete the module and a link to https://www.drupal.org/project/invite_user_relationships

Nah leave as is, the module is still valid for 3.x. I'll update the submodules .info to include that.