diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 7275611d..2b112f90 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -20,7 +20,7 @@ jobs:
     strategy:
       matrix:
         otp:
-          - "28.3"
+          - "28.4"
           - "28.0"
           - "27.3"
           - "27.0"
@@ -48,7 +48,7 @@ jobs:
   examples:
     name: Test examples
     runs-on: ubuntu-latest
-    container: erlang:28.3
+    container: erlang:28.4
     steps:
       - name: Checkout code
         uses: actions/checkout@v6
@@ -58,7 +58,7 @@ jobs:
   parallel-examples:
     name: Test examples in parallel
     runs-on: ubuntu-latest
-    container: erlang:28.3
+    container: erlang:28.4
     steps:
       - name: Checkout code
         uses: actions/checkout@v6
@@ -68,7 +68,7 @@ jobs:
   coverage:
     name: Code coverage
     runs-on: ubuntu-latest
-    container: erlang:28.3
+    container: erlang:28.4
     steps:
       - name: Checkout code
         uses: actions/checkout@v6
diff --git a/README.md b/README.md
index 599f4681..b95f0da9 100644
--- a/README.md
+++ b/README.md
@@ -195,7 +195,7 @@ incompatibilities between the two tools by now.
 <!-- Badges (alphabetically) -->
 [codecov badge]: https://codecov.io/gh/proper-testing/proper/branch/master/graph/badge.svg
 [commit badge]: https://img.shields.io/github/last-commit/proper-testing/proper.svg?style=flat-square
-[erlang versions badge]: https://img.shields.io/badge/erlang-21.3%20to%2028.3-blue.svg?style=flat-square
+[erlang versions badge]: https://img.shields.io/badge/erlang-21.3%20to%2028.4-blue.svg?style=flat-square
 [hex pm badge]: https://img.shields.io/hexpm/v/proper.svg?style=flat
 [license badge]: https://img.shields.io/github/license/proper-testing/proper.svg?style=flat-square
 [release badge]: https://img.shields.io/github/release/proper-testing/proper.svg?style=flat-square