diff --git a/.github/actions/setup-elixir-and-cache-deps/action.yml b/.github/actions/setup-elixir-and-cache-deps/action.yml
index 1c47653858..db2748c05e 100644
--- a/.github/actions/setup-elixir-and-cache-deps/action.yml
+++ b/.github/actions/setup-elixir-and-cache-deps/action.yml
@@ -4,11 +4,11 @@ inputs:
   elixir-version:
     description: "Elixir version"
     required: false
-    default: "1.17.2"
+    default: "1.17.3"
   otp-version:
     description: "OTP version"
     required: false
-    default: "27"
+    default: "26"
   cache-name-deps:
     description: "Cache name for dependencies"
     required: true
diff --git a/CHANGELOG.md b/CHANGELOG.md
index d189910c57..c79a587c0b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,8 @@
 
 ### Improvements and bug fixes
 
+- fix: downgrade elixir from 1.17.2-otp-27 to 1.17.3-otp-26 (#4315 - @swiffer)
+
 #### Build, CI, internal
 
 #### Dashboards
diff --git a/Dockerfile b/Dockerfile
index cf1fadc15b..cd4f04ba7b 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM elixir:1.17.2-otp-27 AS builder
+FROM elixir:1.17.3-otp-26 AS builder
 
 SHELL ["/bin/bash", "-o", "pipefail", "-c"]
 
diff --git a/nix/flake-modules/package.nix b/nix/flake-modules/package.nix
index 594cd15686..fb57cc7069 100644
--- a/nix/flake-modules/package.nix
+++ b/nix/flake-modules/package.nix
@@ -2,8 +2,8 @@
 {
   perSystem = { lib, pkgs, system, ... }:
     let
-      elixir = pkgs.beam.packages.erlang_27.elixir_1_17;
-      beamPackages = pkgs.beam.packagesWith pkgs.beam.interpreters.erlang_27;
+      elixir = pkgs.beam.packages.erlang_26.elixir_1_17;
+      beamPackages = pkgs.beam.packagesWith pkgs.beam.interpreters.erlang_26;
 
       src = ../..;
       version = builtins.readFile "${src}/VERSION";
diff --git a/website/docs/development.md b/website/docs/development.md
index c982302163..ed57ab8271 100644
--- a/website/docs/development.md
+++ b/website/docs/development.md
@@ -6,7 +6,7 @@ sidebar_label: Development and Contributing
 
 ## Requirements
 
-- **Elixir** >= 1.17.2-otp-27
+- **Elixir** >= 1.17.3-otp-26
 - **Postgres** >= 17
 - An **MQTT broker** e.g. mosquitto (_optional_)
 - **NodeJS** >= 20.15.0