Support in-session version updates (important with 1M context)

Problem

With the 1M context window, sessions now last significantly longer — often hours. However, Claude Code no longer supports in-session binary updates (a feature that previously existed). This means users are locked to the version they started with for the entire session duration.

For users with structured session workflows (e.g., context logging, session summaries, state persistence), switching sessions just to pick up a patch version is a 5-10 minute process — not a quick restart.

This creates a tension: the longer sessions enabled by 1M context are exactly the sessions most likely to span multiple version releases.

Suggested solution

Allow in-session binary reload/upgrade without losing conversation state. Possible approaches:

• Hot-reload the binary while preserving the conversation context
• A /upgrade command that restarts the process but reloads the conversation from the serialized state
• At minimum, surface a notification when a newer version is available so users can decide when to switch

Context

• Previously, Claude Code supported in-session auto-updates
• With 200k context windows, sessions were shorter and restarts were less costly
• With 1M context, sessions routinely last long enough that version drift becomes noticeable