diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 8ee7c42..2e5536d 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -17,6 +17,7 @@ jobs:
       fail-fast: false
       matrix:
         ruby-version:
+          - "4.0"
           - "3"
           - "3.4"
           - "3.3"
diff --git a/Gemfile b/Gemfile
index 82cfbfb..7aef0bb 100644
--- a/Gemfile
+++ b/Gemfile
@@ -3,3 +3,5 @@ source "https://rubygems.org"
 gemspec
 
 gem "base64" if RUBY_VERSION >= "3.4.0"
+# No longer a default gem on Ruby 4.0 and TruffleRuby 40, and logtail 0.1.17 requires it undeclared
+gem "logger"