Getting error when script script move to other server.

(nodo: 15707) [DEP0005] DeprecationWarning: Buffer () está en desuso debido a problemas de seguridad y usabilidad. Utilice los métodos Buffer.alloc (), Buffer.allocUnsafe () o Buffer.from () en su lugar.

Versiones actuales:

Ubuntu 16.04.4 LTS  
Node - v10.9.0  
NPM - 6.2.0  

Versión previa

Ubuntu 14.04.3 LTS
NPM - 3.10.10
Node - v6.10.3

exports.basicAuthentication = function (req, res, next) {
    console.log("basicAuthentication");
    if (!req.headers.authorization) {
        return res.status(401).send({
            message: "Unauthorised access"
        });
    }
    var auth = req.headers.authorization;
    var baseAuth = auth.replace("Basic", "");
    baseAuth = baseAuth.trim();
    var userPasswordString = new Buffer(baseAuth, 'base64').toString('ascii');
    var credentials = userPasswordString.split(':');

    var username = credentials[0] !== undefined ? credentials[0] : '';
    var password = credentials[1] !== undefined ? credentials[1] : '';
    var userQuery = {mobilenumber: username, otp: password};
    console.log(userQuery);
    User.findOne(userQuery).exec(function (err, userinfo) {
        if (err || !userinfo) {
             return res.status(401).send({
                message: "Unauthorised access"
             });
        } else {
            req.user = userinfo;
            next();
        }
    });

 }