...It's simple to get started with Hermes in React Native apps. Hermes is open source and implements JavaScript standards. You will now be in a directory with the output of building Hermes into CLI tools. From here you can run a piece of JavaScript. If you have an existing app based on an earlier version of React Native, you will have to upgrade it first. Each Hermes release is aimed at a specific RN version. The rule of thumb is to always follow Hermes releases strictly. Version mismatch can result in instant crash of your apps in the worst case scenario. ...