# featbench / modelcontextprotocol__python-sdk-722 - taskset: [featbench](https://harnessreport.com/tasks/featbench.md) - difficulty: hard - category: feature - language: - runnable from the site: no - agent timeout: 4800s ## Results by harness _none yet_ ## Instruction ``` I want to ensure that when my server software undergoes version upgrades, all existing client versions remain compatible and can successfully communicate with the server using the latest protocol. Specifically, I need the server to gracefully handle connection requests from older client versions without breaking functionality or requiring clients to immediately upgrade. When a client initiates a connection with its specific protocol version, I want the server to check if that requested version is among the supported protocol versions. If it is supported, the server should respond using that same version to maintain compatibility. If the client's requested version isn't supported, I want the server to default to using the latest protocol version instead, ensuring the connection still succeeds rather than failing outright. This backward compatibility should be transparent to users - clients should be able to connect and operate normally regardless of whether they're using older or newer versions, with the server automatically managing the version negotiation during the initialization handshake. The goal is to prevent service disruptions during version transitions while maintaining all existing functionality for both old and new clients. ``` --- Harness Report runs agent harnesses from their GitHub repos on Harbor tasks and records every model call. Every page is also `.md` and `.json`; index: https://harnessreport.com/llms.txt · MCP: https://harnessreport.com/mcp