---
page_type: error
code: 54103
message: "54103: Document revision mismatch"
level: ERROR
product: Sync
---

## Error - 54103

### Sync: Document revision mismatch

The actual revision of the Document does not match the expected revision.

#### Possible Causes

- Your update to this Sync Document has conflicted with a request submitted elsewhere.
- The value specified in the If-Match header is erroneous.

#### Possible Solutions

If your update conflicts with a concurrent update elsewhere, the correct solution is to read the latest revision (on the client SDK: wait for an update) and then re-attempt your update until you succeed. Consider that, since the data has changed, you may not want to submit the exact same update a second time. On the JavaScript SDK, we suggest using the [mutate](/docs/api/sync/mutation-and-conflict-resolution#javascript-sdk-conflict-walkthrough) convenience function.

The value you provide in the If-Match header should be a revision assigned by the Sync service when interacting with an object.

- In SDKs, this is the `revision` field, part of the object descriptor.
- When using REST (e.g. via the Twilio Helper libraries) this is the `ETag` header provided in responses.