diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 9c446d8..9088ebe 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -49,7 +49,7 @@ jobs:
     strategy:
       matrix:
         rails: [ '7.0.1', '7.1.0', '7.2.0' ]
-        ruby: [ '2.7', '3.0', '3.1', '3.2', '3.3', '3.4', '3.5' ]
+        ruby: [ '2.7', '3.0', '3.1', '3.2', '3.3', '3.4', '4.0' ]
         exclude:
           - { rails: '7.2.0', ruby: '2.7' }
           - { rails: '7.2.0', ruby: '3.0' }
@@ -63,4 +63,4 @@ jobs:
     strategy:
       matrix:
         rails: [ '8.0.0', '8.1.0' ]
-        ruby: [ '3.2', '3.3', '3.4', '3.5' ]
+        ruby: [ '3.2', '3.3', '3.4', '4.0' ]
diff --git a/CHANGELOG.markdown b/CHANGELOG.markdown
index 5d27c49..25dd28a 100644
--- a/CHANGELOG.markdown
+++ b/CHANGELOG.markdown
@@ -1,3 +1,7 @@
+#### Unreleased
+* Replace Ruby 3.5 with Ruby 4.0 in all rspec tests
+  > emmahsax: https://github.com/emmahsax/okcomputer/pull/22
+
 #### v1.19.1
 * Add rspec for higher versions of Ruby and Rails
   > emmahsax: https://github.com/emmahsax/okcomputer/pull/19