Appwrite Functions runtime version change impact on existing deployed functions

When Appwrite updates the default Node.js runtime version for Functions, it is unclear whether existing deployed functions are automatically migrated to the new runtime or require a manual redeploy to continue operating.

This ambiguity affects dependency compatibility, environment variable handling, and cold‑start performance, especially for self‑hosted installations where administrators control upgrade timing.

What determines the migration path for existing functions when the platform runtime default changes? Is the behavior consistent across cloud and self‑hosted deployments, and where is this policy documented?