# Release Notes
Recent updates and changes to the xAI API.
## Latest Updates
### Grok 4.1 Fast
You can now use Grok 4.1 Fast in the xAI Enterprise API, including with agent tools.
**Models available:**
- `grok-4-1-fast-reasoning` - With reasoning capabilities
- `grok-4-1-fast-non-reasoning` - Without reasoning, optimized for speed
### Files API
You can upload files and use them in chat conversations with the Files API.
**Requirements:**
- Version 1.4.0 of the `xai-sdk` package required
### Agentic Tool Calling
Enhanced agentic tool calling capabilities with automatic tool orchestration.
**Requirements:**
- Version 1.3.1 of the `xai-sdk` package required
### Inline Citations
Responses can now include inline citations with structured metadata.
**Requirements:**
- Version 1.5.0 of the `xai-sdk` package required
### Location-Based Search
Search tools now support location-based queries for more relevant results.
**Requirements:**
- Version 1.6.0 of the `xai-sdk` package required
### Collections API
Upload files, create embeddings, and use them for inference with the Collections API.
- Organize documents into collections
- Search across documents
- Receive cited responses
### Grok 4 Fast
xAI has released grok-4-fast, the latest advancement in cost-efficient reasoning models.
**Specifications:**
- Context window: 2,000,000 tokens
- Pricing: $0.20 input / $0.50 output per million tokens
- Balanced speed and quality
### Voice Agent API
New real-time voice conversation capabilities via WebSocket.
**Features:**
- 100+ languages supported
- Native-quality accents
- Real-time bidirectional audio
- Tool calling support
## SDK Version History
| Version | Features Added |
|---------|----------------|
| 1.6.0 | Location-based search |
| 1.5.0 | Inline citations |
| 1.4.0 | Files API, `get_tool_call_type` |
| 1.3.1 | Agentic tool calling |
## API Changes
### Responses API (Preferred)
The Responses API is now the preferred method for new integrations, offering:
- Simplified interface
- Built-in tool support
- Streaming support
### Chat Completions (Legacy)
Chat Completions API remains available for backward compatibility but Responses API is recommended for new projects.
### Model Aliases
Models now support aliases for easier migration:
- `<modelname>` → Latest stable version
- `<modelname>-latest` → Latest version with newest features
- `<modelname>-<date>` → Specific release
## Breaking Changes
### Reasoning Model Parameters
Grok 4 reasoning models do not support:
- `presencePenalty`
- `frequencyPenalty`
- `stop`
- `reasoning_effort`
Requests with these parameters will return errors.
## Deprecations
### Chat Completions
While still functional, Chat Completions is considered legacy. Migrate to Responses API for new features.
## Migration Guide
See [Migrating to New Models](./migration.md) for detailed migration instructions.
## Known Issues
Check https://status.x.ai for current service status and known issues.
## Getting Help
- Documentation: https://docs.x.ai
- Support: support@x.ai
- Status: https://status.x.ai
