When enabling the Submitter Mode Locked option (and reboot the system) so someone can modify tickets they submit without the need of a write license, can we add a group to the field and expect that someone without a write license but belonging to that group and their name in the Submitter field should be able to modify the field?
It was understood we have to add the implicit group Submitter to the fields you want someone with a write license to be able to modify and that this is the only group we look at for that person without a write license. Is this correct?

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Legacy ID:KA331105

The Submitter Locked mode has nothing to do with permissions. It has to do with licenses.

- If Submitter Locked is TRUE, a user does not need a license to modify a ticket where the login name is entered in the Submitter field.
- If Submitter Locked is FALSE, the user does need a license.

Now, separate than the license, the user also needs permission to perform the update. If they are granted permission IN ANY WAY to update the entry, then they can. So, granting Public change access will allow the submitter to change their own entry.
Granting access using the implicit groups (Submitter, Assignee, or Assignee Group) will work. Granting access with an explicit group will work. If the user has permission to update a field, they can.

In short, the Submitter Locked mode is not tied to the Submitter group. One controls licensing, the other is involved in permissions.