--- 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 --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Release v0.42.0 · jj-vcs/jj **[Lobsters](https://daily.dev/sources/lobsters)** · 3 min read · 2 upvotes · 0 comments ## Summary 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. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Release v0.43.0 · jj-vcs/jj](https://daily.dev/posts/release-v0-43-0-jj-vcs-jj-qm3dne69f) · Lobsters · 1 upvotes · 0 comments - [Release v0.34.0 · jj-vcs/jj](https://daily.dev/posts/release-v0-34-0-jj-vcs-jj-t9jityd9c) · Lobsters · 3 upvotes · 0 comments - [Release v0.41.0 · jj-vcs/jj](https://daily.dev/posts/release-v0-41-0-jj-vcs-jj-ezj5qmnvy) · Lobsters · 2 upvotes · 0 comments --- Tags: [#git](https://daily.dev/tags/git), [#version-control](https://daily.dev/tags/version-control) [View this post on daily.dev](https://daily.dev/posts/release-v0-42-0-jj-vcs-jj-vxmazbglw) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Release v0.42.0 · jj-vcs/jj","url":"https://daily.dev/posts/release-v0-42-0-jj-vcs-jj-vxmazbglw","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/release-v0-42-0-jj-vcs-jj-vxmazbglw"},"datePublished":"2026-06-05T00:01:27.216Z","dateModified":"2026-06-05T00:01:50.857Z","description":"jj v0.42.0 is released with a switch to the mimalloc memory allocator for improved multi-threaded performance. 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