[Release] google/adk-python v1.25.1: v1.25.1

Google ADK Python v1.25.1 release fixes pickling lock errors in McpSessionManager. This patch update addresses a bug that was preventing proper serialization of session manager objects.

Key Points

• •Version 1.25.1 released on 2026-02-18 for google/adk-python
• •Primary fix addresses pickling lock errors in McpSessionManager component
• •Pickling errors were preventing proper serialization of session manager objects
• •McpSessionManager is a critical component for managing MCP (Model Context Protocol) sessions
• •Bug fix improves reliability of session persistence and distributed processing
• •Update recommended for users experiencing serialization issues with session management

Concepts