League\Monga\Query\Update::upsert PHP Method

Set the upsert option.

public upsert ( boolean $upsert = true ) : object
$upsert	boolean	whether to allow upserts
return	object	$this

    public function upsert($upsert = true)
    {
        $this->upsert = (bool) $upsert;
        return $this;
    }

Update