diff --git a/.github/workflows/actions.yml b/.github/workflows/actions.yml
index 03f18a0..2acfc9d 100644
--- a/.github/workflows/actions.yml
+++ b/.github/workflows/actions.yml
@@ -11,7 +11,7 @@ jobs:
       BUNDLE_DEPLOYMENT: "false" # do not fail test when bumping release without bundling
     strategy:
       matrix:
-        ruby: [ '2.5', '2.6', '2.7', '3.0', truffleruby-head ] # lowest must match ruby version in gemspec
+        ruby: [ '2.6', '3.4', '4.0' ] # lowest must match ruby version in gemspec
         task: [ 'default' ]
     name: ${{ matrix.ruby }} rake ${{ matrix.task }}
     steps:
diff --git a/.ruby-version b/.ruby-version
new file mode 100644
index 0000000..7636e75
--- /dev/null
+++ b/.ruby-version
@@ -0,0 +1 @@
+4.0.5
diff --git a/Gemfile b/Gemfile
index cd34144..9980d8a 100644
--- a/Gemfile
+++ b/Gemfile
@@ -3,5 +3,5 @@ source "https://rubygems.org"
 gemspec
 
 gem 'rake'
-gem 'rspec', '~>2'
+gem 'rspec', '~>3'
 gem 'bump'
diff --git a/Gemfile.lock b/Gemfile.lock
index a2aaeba..70e1cf0 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -7,26 +7,27 @@ GEM
   remote: https://rubygems.org/
   specs:
     bump (0.10.0)
-    diff-lcs (1.4.4)
-    rake (13.0.6)
-    rspec (2.99.0)
-      rspec-core (~> 2.99.0)
-      rspec-expectations (~> 2.99.0)
-      rspec-mocks (~> 2.99.0)
-    rspec-core (2.99.2)
-    rspec-expectations (2.99.2)
-      diff-lcs (>= 1.1.3, < 2.0)
-    rspec-mocks (2.99.4)
+    diff-lcs (1.6.2)
+    rake (13.4.2)
+    rspec (3.13.2)
+      rspec-core (~> 3.13.0)
+      rspec-expectations (~> 3.13.0)
+      rspec-mocks (~> 3.13.0)
+    rspec-core (3.13.6)
+      rspec-support (~> 3.13.0)
+    rspec-expectations (3.13.5)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.13.0)
+    rspec-mocks (3.13.8)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.13.0)
+    rspec-support (3.13.7)
 
 PLATFORMS
-  x86_64-darwin-19
-  x86_64-linux
+  ruby
 
 DEPENDENCIES
   bump
   pru!
   rake
-  rspec (~> 2)
-
-BUNDLED WITH
-   2.2.16
+  rspec (~> 3)
diff --git a/pru.gemspec b/pru.gemspec
index 84f0b3a..b5f35c0 100644
--- a/pru.gemspec
+++ b/pru.gemspec
@@ -10,5 +10,6 @@ Gem::Specification.new name, Pru::VERSION do |s|
   s.files = `git ls-files lib`.split("\n")
   s.license = "MIT"
   s.executables = ["pru"]
-  s.required_ruby_version = '>= 2.5' # must match lowest in .github/workflows/actions.yml
+  # 2.6 because that is sadly what is available by default on macs
+  s.required_ruby_version = '>= 2.6' # must match lowest in .github/workflows/actions.yml
 end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 4acc563..14d9fbe 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -1,2 +1,6 @@
 require 'pru'
 require 'pru/version'
+
+RSpec.configure do |config|
+  config.expect_with(:rspec) { |c| c.syntax = [:should, :expect] }
+end