Mojo Hits 1.0 with an Explicit 1.x Stability Promise — and a Commitment to Open-Source the Compiler This Year

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Modular shipped Mojo 1.0 as part of the 26.5 release on August 11 (408 points on HN). The substance is stability: during the 1.x timeframe changes should be primarily additive, so the language stops shifting under existing code. The release adds Python-style lambda syntax, unified closure handling, a single consolidated Pointer type, consistent `var` declarations, memory-safety diagnostics for reference invalidation, and a more stable LSP server. Modular reports nearly 200 contributors landing 1,100+ pull requests across 200,000+ lines, and commits to open-sourcing the Mojo compiler and toolchain in 2026 — the remaining reason many GPU developers have stayed away.