# Upgrading Signatures v6 to v15

In this section we introduce you to the features of signatures v15 and what you need to consider when upgrading from v6 to this version.

## v15 changes

### Signing version header

To be able to make requests with v15 of the signing, you must add a special version header.

**Example**


```
upvest-signature-version: 15
```

### HTTP request body `digest` and `content-digest`

In v15 of signing, the component `digest` has been deprecated and replaced by the component `content-digest`.

Follow these steps to calculate `content-digest`:

Capture the entire byte stream of the request body.


Calculate the [SHA-512](https://datatracker.ietf.org/doc/html/rfc6234) hash of the body content.


Encode the resulting value using [Base64 encoding](https://datatracker.ietf.org/doc/html/rfc4648).


Add a request header named `content-digest` with the following value: `sha-512=:{digest value}:`, where `{digest value}` is replaced by the result of the previous step. Please note that `{digest value}` is enclosed in colons (`:`).

**Example**

| Request body | Content length | `content-digest` header value |
|  --- | --- | --- |
| {"hello": "world"} | 18 | `"sha-512=:WZDPaVn/7XgHaAy8pmojAkGWoRx2UFChF41A2svX+TaPm+AbwAgBWnrIiYllu7BNNyealdVLvRwEmTHWXvJwew==:` |
| {"key": "value"} | 16 | `sha-512=:Hd9/AvGZkbjitW1+Ml8Fg1ux1mtcDYe6mLQjDyoowIWa3LM/PmwN2v9O+MjtQGrCA3EQWUL54dlgxKHyYbrucw==:` |


### Calculating the signature components

In v15 of signing, signature components keys should be quoted in the signature base string:

**Example for V15**


```
"@method": POST
"@path": /endpoint
"@query": ?a=b
"accept": application/json
"authorization": Bearer access-token
"content-length": 16
"content-type": application/json
"content-digest": sha-512=:Hd9/AvGZkbjitW1+Ml8Fg1ux1mtcDYe6mLQjDyoowIWa3LM/PmwN2v9O+MjtQGrCA3EQWUL54dlgxKHyYbrucw==:
"idempotency-key": 2133825797664cad
"upvest-client-id": 5ec16164-6173-461d-b90d-116d68f55b40
```

## Next steps

In the tutorial ['Implementing HTTP signatures v15'](/products/byol/getting_started/http_signatures/implementing_http_signatures_v15) you can find the detailed description.