--- title: Release v0.42.0 · jj-vcs/jj | daily.dev description: jj v0.42.0 is released with a switch to the mimalloc memory allocator for improved multi-threaded performance. New features include shell completions surfacing... canonical: https://daily.dev/posts/release-v0-42-0-jj-vcs-jj-vxmazbglw twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Release v0.42.0 · jj-vcs/jj | daily.dev og:description: jj v0.42.0 is released with a switch to the mimalloc memory allocator for improved multi-threaded performance. New features include shell completions surfacing... og:url: https://daily.dev/posts/release-v0-42-0-jj-vcs-jj-vxmazbglw og:image: https://api.daily.dev/og/posts/VxMaZbGLW.png og:image:alt: Release v0.42.0 · jj-vcs/jj og:image:width: 1200 og:image:height: 630 og:locale: en --- [Lobsters](https://daily.dev/sources/lobsters) [Read post](https://api.daily.dev/r/VxMaZbGLW) # [Release v0.42.0 · jj-vcs/jj](https://api.daily.dev/r/VxMaZbGLW "Go to post") jj v0.42.0 is released with a switch to the mimalloc memory allocator for improved multi-threaded performance. New features include shell completions surfacing descriptions for custom aliases, \`jj show\` accepting multiple revisions, \`jj git fetch\` generating evolution history based on change IDs, a new \`jj util backend name\` command, and a new \`edit-invocation-mode\` config option enabling per-file diff editing. Several deprecated command and config options have been removed, and multiple bugs have been fixed including a panic on empty remote names and improved color-words diff readability when color output is disabled. [#git](/tags/git "Check all #git posts")[#version-control](/tags/version-control "Check all #version-control posts") Jun 05•3m read time•From [github.com](https://api.daily.dev/r/VxMaZbGLW "github.com") [](https://api.daily.dev/r/VxMaZbGLW "Go to post") Table of contents [About](https://api.daily.dev/r/VxMaZbGLW "About")[Release highlights](https://api.daily.dev/r/VxMaZbGLW "Release highlights")[Breaking changes](https://api.daily.dev/r/VxMaZbGLW "Breaking changes")[Deprecations](https://api.daily.dev/r/VxMaZbGLW "Deprecations")[New features](https://api.daily.dev/r/VxMaZbGLW "New features")[Fixed bugs](https://api.daily.dev/r/VxMaZbGLW "Fixed bugs")[Contributors](https://api.daily.dev/r/VxMaZbGLW "Contributors") 5.7K Impressions2 Upvotes Comment Bookmark Copy Share your thoughtsPost [](https://daily.dev/sources/lobsters) [Lobsters](https://daily.dev/sources/lobsters "https://daily.dev/sources/lobsters") Lobsters is a community-driven platform for sharing and discussing links to articles, tutorials, and... 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