---
title: contentModificationDateKey
framework: foundation
role: symbol
role_heading: Type Property
path: foundation/urlresourcekey/contentmodificationdatekey
---

# contentModificationDateKey

The time at which the resource was most recently modified.

## Declaration

```swift
static let contentModificationDateKey: URLResourceKey
```

## Discussion

Discussion This key corresponds to an NSDate value, or nil if the volume doesn’t support modification dates. The corresponding resource is read-write. important: This API has the potential of being misused to access device signals to try to identify the device or user, also known as fingerprinting. Regardless of whether a user gives your app permission to track, fingerprinting is not allowed. When you use this API in your app or third-party SDK (an SDK not provided by Apple), declare your usage and the reason for using the API in your app or third-party SDK’s PrivacyInfo.xcprivacy file. For more information, including the list of valid reasons for using the API, see Describing use of required reason API.

## See Also

### Other resource keys

- [keysOfUnsetValuesKey](foundation/urlresourcekey/keysofunsetvalueskey.md)
- [quarantinePropertiesKey](foundation/urlresourcekey/quarantinepropertieskey.md)
- [addedToDirectoryDateKey](foundation/urlresourcekey/addedtodirectorydatekey.md)
- [attributeModificationDateKey](foundation/urlresourcekey/attributemodificationdatekey.md)
- [contentAccessDateKey](foundation/urlresourcekey/contentaccessdatekey.md)
- [creationDateKey](foundation/urlresourcekey/creationdatekey.md)
- [customIconKey](foundation/urlresourcekey/customiconkey.md)
- [documentIdentifierKey](foundation/urlresourcekey/documentidentifierkey.md)
- [effectiveIconKey](foundation/urlresourcekey/effectiveiconkey.md)
- [generationIdentifierKey](foundation/urlresourcekey/generationidentifierkey.md)
- [hasHiddenExtensionKey](foundation/urlresourcekey/hashiddenextensionkey.md)
- [isExcludedFromBackupKey](foundation/urlresourcekey/isexcludedfrombackupkey.md)
- [isExecutableKey](foundation/urlresourcekey/isexecutablekey.md)
- [isHiddenKey](foundation/urlresourcekey/ishiddenkey.md)
- [isReadableKey](foundation/urlresourcekey/isreadablekey.md)