---
title: manifestVersion
framework: webkit
role: symbol
role_heading: Instance Property
path: webkit/wkwebextension/manifestversion
---

# manifestVersion

The parsed manifest version, or 0 if there is no version specified in the manifest.

## Declaration

```swift
var manifestVersion: Double { get }
```

## Discussion

Discussion note: A unsupportedManifestVersion error will be reported if the manifest version isn’t specified.