---
title: "fetchPersistentChanges(since:)"
framework: photos
role: symbol
role_heading: Instance Method
path: "photos/phphotolibrary/fetchpersistentchanges(since:)"
---

# fetchPersistentChanges(since:)

Retrieves the Photos library changes since the token you specify.

## Declaration

```swift
func fetchPersistentChanges(since token: PHPersistentChangeToken) throws -> PHPersistentChangeFetchResult
```

## Parameters

- `token`: The token that represents the state of the Photos library to compare against.

## Mentioned in

Uploading asset resources in the background

## Return Value

Return Value A fetch result that contains library change details; otherwise, an error that indicates why the fetch fails (for example, PHPhotosError.Code.persistentChangeTokenExpired).

## See Also

### Fetching Change History

- [PHPersistentChangeFetchResult](photos/phpersistentchangefetchresult.md)
- [currentChangeToken](photos/phphotolibrary/currentchangetoken.md)
- [PHPersistentChangeToken](photos/phpersistentchangetoken.md)