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+# Microsoft 365 Agents SDK for Python - Release Notes v0.6.1
+
+**Release Date:** December 1, 2025  
+**Previous Version:** 0.6.0 (Released November 18, 2025)
+
+## Overview
+
+This is a patch release that includes important bug fixes and build process improvements. Version 0.6.1 ensures reliable package versioning and fixes a serialization issue in the OAuth flow.
+
+---
+
+## 🔧 Build & Packaging Improvements
+
+### Package Version File Support
+
+Updated the versioning mechanism for all Python library packages to ensure consistent and reliable version management.
+
+**Changes:**
+- Build process now writes package version to a `VERSION.txt` file in each library directory
+- All `setup.py` files updated to read version from `VERSION.txt` (falls back to environment variable)
+- Added `MANIFEST.in` files to include `VERSION.txt` in built packages
+
+**Affected Libraries:**
+- `microsoft-agents-activity`
+- `microsoft-agents-authentication-msal`
+- `microsoft-agents-copilotstudio-client`
+- `microsoft-agents-hosting-aiohttp`
+- `microsoft-agents-hosting-core`
+- `microsoft-agents-hosting-fastapi`
+- `microsoft-agents-hosting-teams`
+- `microsoft-agents-storage-blob`
+- `microsoft-agents-storage-cosmos`
+
+**Pull Requests:**
+- [#261 - Getting package version from file when building packages](https://github.com/microsoft/Agents-for-python/pull/261)
+- [#263 - Adding MANIFEST.in file to include package version files in builds](https://github.com/microsoft/Agents-for-python/pull/263)
+
+---
+
+## 🐛 Bug Fixes
+
+### OAuth SignInState Serialization Fix
+
+Fixed serialization and deserialization issues with the `_SignInState` class in the OAuth flow.
+
+**Changes:**
+- Refactored `_SignInState` class to use Pydantic's `BaseModel` for data modeling and validation
+- Updated serialization methods to use Pydantic's `model_dump` and `model_validate` utilities
+- Improved maintainability and code clarity
+
+**Pull Request:**
+- [#264 - Fixing _sign_in_state serialization/deserialization](https://github.com/microsoft/Agents-for-python/pull/264)
+
+---
+
+## 📦 Package Information
+
+### Included Libraries
+
+All 9 core libraries are included in this release:
+
+1. **microsoft-agents-activity** - Core activity models and handling
+2. **microsoft-agents-authentication-msal** - MSAL authentication integration
+3. **microsoft-agents-copilotstudio-client** - Copilot Studio client connectivity
+4. **microsoft-agents-hosting-aiohttp** - AIOHTTP-based agent hosting
+5. **microsoft-agents-hosting-core** - Core hosting functionality and abstractions
+6. **microsoft-agents-hosting-fastapi** - FastAPI-based agent hosting
+7. **microsoft-agents-hosting-teams** - Microsoft Teams-specific hosting
+8. **microsoft-agents-storage-blob** - Azure Blob Storage integration
+9. **microsoft-agents-storage-cosmos** - Azure Cosmos DB storage integration
+
+### Python Version Support
+
+- **Supported Versions:** Python 3.10, 3.11, 3.12, 3.13, 3.14
+- **Minimum Required:** Python 3.10
+
+---
+
+## 🚀 Upgrading
+
+To upgrade to version 0.6.1, update your packages using pip:
+
+```bash
+pip install --upgrade microsoft-agents-activity==0.6.1
+pip install --upgrade microsoft-agents-hosting-core==0.6.1
+# ... other packages as needed
+```
+
+---
+
+## 📞 Support & Resources
+
+- **Documentation:** [Microsoft 365 Agents SDK](https://aka.ms/agents)
+- **Issues:** [GitHub Issues](https://github.com/microsoft/Agents-for-python/issues)
+- **Samples:** [Agent Samples Repository](https://github.com/microsoft/Agents)
+
+For technical support and questions, please use the GitHub Issues page or refer to our comprehensive documentation and samples.