- Introduces Helm Plugin Manager with simple install/remove commands, local development workflow, and plugin hooks system
- Adds new templating functions (required, toToml, expanded Sprig), value hoisting from child to parent charts, and new Chart.yaml fields appVersion and deprecated
- Enables TLS encryption for Helm‑Tiller gRPC communication, adds weighted hooks, reuse‑values and skip‑refresh flags, plus many bug fixes and documentation updates