City of Stephenson issued the following announcement on Oct 22.
Beginning this Sunday, October 24th, the 906 area code MUST be dialed for all local calls. Calls made without the 906 area code may not be connected.
The 10-digit dialing requirement is related to the July 2022 rollout of the 9-8-8 National Suicide Prevention Lifeline telephone number. This change will affect 82 jurisdictions across the nation that currently use a 988 local prefix, including a portion of Ontonogon County in the U.P.
Original source can be found here.