# TypeScript App Troubleshooting

### Build error during a deploy

TypeScript apps will fail to deploy when a feature is not compatible with your app's [`@journeyapps/runtime-build`](https://docs.journeyapps.com/reference/build/syntax/typescript-apps/runtime-build-package) package version. The error shown in the build logs will typically be along the lines of: 

`Property <PropertyName> does not exist on interface <InterfaceName>`

To resolve this, [upgrade your `@journeyapps/runtime-build` package to a newer version](https://docs.journeyapps.com/reference/build/syntax/runtime-build-package#how-to-update-your-apps-runtime-build-version).