diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 65fced5..d6c5b6e 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -11,7 +11,7 @@ jobs:
     uses: ruby/actions/.github/workflows/ruby_versions.yml@master
     with:
       engine: cruby
-      min_version: 2.7
+      min_version: 3.0
 
   test:
     needs: ruby-versions
diff --git a/lib/pp.rb b/lib/pp.rb
index 6060282..951d942 100644
--- a/lib/pp.rb
+++ b/lib/pp.rb
@@ -64,7 +64,7 @@
 class PP < PrettyPrint
 
   # The version string
-  VERSION = "0.6.2"
+  VERSION = "0.7.0.dev1"
 
   # Returns the usable width for +out+.
   # As the width of +out+:
diff --git a/pp.gemspec b/pp.gemspec
index 15a3b4d..c15d8f5 100644
--- a/pp.gemspec
+++ b/pp.gemspec
@@ -16,7 +16,7 @@ Gem::Specification.new do |spec|
   spec.homepage      = "https://github.com/ruby/pp"
   spec.licenses      = ["Ruby", "BSD-2-Clause"]
 
-  spec.required_ruby_version = Gem::Requirement.new(">= 2.7.0")
+  spec.required_ruby_version = Gem::Requirement.new(">= 3.0.0")
 
   spec.metadata["homepage_uri"] = spec.homepage
   spec.metadata["source_code_uri"] = spec.homepage