v1.39.0

PostHog/posthog.comv1.39.0Mar 6, 2026by Schniz

AI Summary

This release focuses on performance and UX improvements for the Fast Node Manager (fnm) tool, specifically optimizing shell startup and improving the robustness of the `--use-on-cd` hook. It introduces a new automatic version switching flag and updates the Rust toolchain.

Key Highlights

Shell startup is now faster by eliminating an extra subprocess during `fnm env` execution
Improved robustness of the `--use-on-cd` shell hook with fixes for zsh deduplication and Windows CMD
New `fnm install --use` flag to automatically switch to the version after installation
Rust toolchain upgraded to version 1.88

New Features

`fnm default` (with no arguments) now returns the current default version

Full Release Notes

**Performance & UX Improvements:**
- Shell startup is now faster: `fnm env --use-on-cd` applies the initial version during `fnm env` itself, eliminating an extra `fnm use` subprocess
- Improved `--use-on-cd` shell hook robustness (zsh hook deduplication on re-source, Windows CMD fixes for paths with spaces and drive changes)

**New Features:**
- `fnm install --use` flag to automatically switch to the version after installing
- `fnm default` (with no arguments) now returns the current default version

**Internal:**
- Rust toolchain upgraded to 1.88

**Docs/Maintenance:**
- Various README improvements, typo fixes, and CI workflow fixes

**Thanks to the new contributors:** @SunsetTechuila, @MangelMaxime, @CodingWithAnxiety, @zeroberry, @isaacl :hat-tip: