diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 6e6fb7a..da8f6fb 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -18,6 +18,9 @@ jobs:
       fail-fast: false
       matrix:
         ruby:
+          - '4.0'
+          - '3.4'
+          - '3.3'
           - '3.2'
           - '3.1'
           - '3.0'
diff --git a/.ruby-version b/.ruby-version
index 944880f..7636e75 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-3.2.0
+4.0.5
diff --git a/Gemfile b/Gemfile
index fa75df1..3861743 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,3 +1,5 @@
 source 'https://rubygems.org'
 
 gemspec
+
+gem "benchmark"