The sdk-for-nodejs buildpack v3.27 includes updated v6 and v8 runtimes.
The buildpack contains the following Node.js runtimes: v4.8.5, v4.8.7, v6.17.0, v6.17.1, 8.15.1, v8.16.0, v10.15.0 and v10.15.3. An existing application will not be affected by the new buildpack until you redeploy it. New applications will automatically use the new buildpack.