As far as I’m aware, unless you’re (a) moving your forum to a different host by creating a backup and restoring it elsewhere or (b) changing your forum’s domain, nothing you do to your forum’s server should have any impact on user sessions.
As far as I’m aware, unless you’re (a) moving your forum to a different host by creating a backup and restoring it elsewhere or (b) changing your forum’s domain, nothing you do to your forum’s server should have any impact on user sessions.