> For the complete documentation index, see [llms.txt](https://firstoken.gitbook.io/api-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://firstoken.gitbook.io/api-docs/guides/implementing-captures-sdk-js/sdk-versions.md).

# SDK versions

Staying current with SDK versions helps developers take advantage of the latest capabilities and enhancements offered.

<table data-full-width="true"><thead><tr><th width="308.76171875">URL</th><th width="100.625">Version</th><th>Integrity</th><th>Changes</th></tr></thead><tbody><tr><td><a href="https://cdn.firstoken.co/captures/js/2.3/sdk.js">https://cdn.firstoken.co/captures/js/2.3/sdk.js</a></td><td>v2.3</td><td>sha256-D0P+mQ7N6E0tbReEGYNTjoGqRmWUX87oCLd8PNvs5vg=</td><td>Content encryption, JWT authentication, enhanced security. <strong>100% Backward Compatible</strong></td></tr><tr><td><a href="https://cdn.firstoken.co/captures/js/2.2/sdk.js">https://cdn.firstoken.co/captures/js/2.2/sdk.js</a></td><td>v2.2</td><td>sha256-IzmJZo/gWd+To2rEV/ZC9+fXZZgHfw5E0jZECyq9ipY=</td><td>Added support for Google Fonts ('Lato', 'Montserrat', 'Open Sans', 'Oswald', 'Poppins', 'Roboto', 'Raleway', 'Slabo 13px', 'Slabo 27px', 'PT Sans', 'Inter') in the font-family CSS</td></tr><tr><td><a href="https://cdn.firstoken.co/captures/js/2.1/sdk.js">https://cdn.firstoken.co/captures/js/2.1/sdk.js</a></td><td>v2.1</td><td>sha256-FbadlNL2dab5uMHBUpFv+jEKsUSg3Cmi0dYvVWQIuZs=</td><td>Added support for tags parameter in the initialization function.</td></tr><tr><td><a href="https://cdn.firstoken.co/captures/js/2.0/sdk.js">https://cdn.firstoken.co/captures/js/2.0/sdk.js</a></td><td>v2.0</td><td>sha256-qtSTst/JgM5bN+4ZILzXN/DEgAhg2jDYgH5pF9YqeNY=</td><td>Added separate date validation events.</td></tr><tr><td><a href="https://cdn.firstoken.co/captures/js/1.0/sdk.js">https://cdn.firstoken.co/captures/js/1.0/sdk.js</a></td><td>v1.0</td><td>sha256-5VzwvLiVo4k8snm84TZShTmTWzXBbCM8NyNMXdkx8fw=</td><td>Original version</td></tr></tbody></table>

### Implementation Recommendations

#### For New Implementations

**Use SDK 2.3** with these options:

#### **Standard Security (Quick Start)**

```html
<script src="https://cdn.firstoken.co/captures/js/2.3/sdk.js"></script>
<script>
const FT = window.FTCaptures.init("your-route-id", "production", callback);
</script>
```

#### **Enhanced Security (Recommended)**

```html
<script src="https://cdn.firstoken.co/captures/js/2.3/sdk.js"></script>
<script>
const FT = window.FTCaptures.init("your-route-id", "production", callback, tags, jwtToken);
</script>
```

### Integrity Verification

Always use integrity hashes in production:

```html
<script 
    src="https://cdn.firstoken.co/captures/js/2.3/sdk.js"
    integrity="sha256-D0P+mQ7N6E0tbReEGYNTjoGqRmWUX87oCLd8PNvs5vg="
    crossorigin="anonymous">
</script>
```

### Version Migration Guides

#### Migrating from 2.2 to 2.3

1. **Update CDN URL**

   ```html
   <!-- Before -->
   <script src="https://cdn.firstoken.co/captures/js/2.2/sdk.js"></script>

   <!-- After -->
   <script src="https://cdn.firstoken.co/captures/js/2.3/sdk.js"></script>
   ```
2. **Test functionality** - All existing features continue to work
3. **Optional: Implement JWT** for enhanced security
4. **Optional:** If you need to encrypt the payload you sent to us, please contact the support team to configure this feature in the inbound route you are using.

### Resources

* [Full Example Guide](/api-docs/guides/implementing-captures-sdk-js/full-example-of-usage.md) - Detailed implementation help
* [Migration & Compatibility](/api-docs/guides/implementing-captures-sdk-js/migration-and-compatibility.md) - Upgrade assistance
* [JWT Authentication Guide](/api-docs/guides/implementing-captures-sdk-js/jwt-authentication-for-firstoken-sdk.md) - Security enhancement