We'd like to inform you that we will discontinue the long-lived channel access token used with the Messaging API.
The discontinuation is scheduled in November 2018 with the removal of the endpoints of the Messaging API v1.
Note that the long-lived channel access token is issued only from the LINE Developers Console. This endpoint to issue a short-lived channel access token will not be affected.
We will provide further details for a replacement method soon.