Elixir v1.20.0-rc.5 released!

NewsBot · 13 May 2026 21:22

Elixir v1.20.0-rc.5 has been released.

This release requires Erlang/OTP 27+ and is compatible with Erlang/OTP 29.

1. Enhancements

EEx

[EEx] Optimize compiler by flattening expr list only once

Elixir

[Base] Optimize Base validation functions by using SWAR techniques

[Float] Optimize Float.round/2 by avoiding big integers

[Inspect] Increase inspect limit to help print deeply nested data structures

[Inspect] Support printing Erlang records (using Erlang notation)

[Kernel] Add occurrence typing on case, cond, and with

[Registry] Switch {:duplicate, :key} key_ets to ordered_set with composite keys

[String] SWAR-optimize ASCII fast paths in String.length/1 and String.slice/3

ExUnit

[ExUnit] Show remaining runs when using --repeat-until-failure

IEx

[IEx.Helpers] Add source/1

Mix

[mix app.tree] Support --output option

[mix deps.tree] Support --output option

[mix help] Support printing docs for types and callbacks

[mix format] Support --no-compile option

[mix source] Add mix source MODULE to print or open a given module/function location

2. Potential breaking changes

Elixir

[Kernel] Disallow raw CR line ending in strings, comments and after ? for security reasons

3. Bug fixes

Elixir

[Kernel] Fix a compiler crash when importing a module with only: :sigils option when the imported module exports non-sigil symbols with sigil_ prefix

[Kernel] Reject negative Duration in to_timeout/1

[Macro] Fix generation of heredocs in Macro.to_string/1 with escaped trailing newline

[Path] Consistently return path as binary in Path.relative_to_cwd/2

[Stream] Raise in Stream.cycle/1 when enumerable reduce call yields no elements

[String] Support empty pattern list in String.count/2

Logger

[Logger] Persist log level to app env in Logger.configure/1

Mix

[Mix] Use…

Link: Release v1.20.0-rc.5 · elixir-lang/elixir · GitHub