diff --git a/.github/workflows/tests-and-linter.yml b/.github/workflows/tests-and-linter.yml
index 7e0b25f..65fc692 100644
--- a/.github/workflows/tests-and-linter.yml
+++ b/.github/workflows/tests-and-linter.yml
@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby: [2.5, 2.6, 2.7, '3.0']
+        ruby: [3.0, 3.1, 3.2]
 
     steps:
       - uses: actions/checkout@v2
diff --git a/.ruby-version b/.ruby-version
index ecd7ee5..818bd47 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-2.5.8
+3.0.6
diff --git a/.tool-versions b/.tool-versions
new file mode 100644
index 0000000..d6608a7
--- /dev/null
+++ b/.tool-versions
@@ -0,0 +1 @@
+ruby 3.0.6
diff --git a/Gemfile.lock b/Gemfile.lock
index ed5da52..caa629b 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -14,18 +14,20 @@ GEM
     e2mmap (0.1.0)
     jaro_winkler (1.5.4)
     maruku (0.7.3)
-    mini_portile2 (2.4.0)
-    nokogiri (1.10.10)
-      mini_portile2 (~> 2.4.0)
-    parallel (1.21.0)
+    mini_portile2 (2.8.4)
+    nokogiri (1.15.4)
+      mini_portile2 (~> 2.8.2)
+      racc (~> 1.4)
+    parallel (1.23.0)
     parser (2.7.2.0)
       ast (~> 2.4.1)
-    rainbow (3.0.0)
+    racc (1.7.1)
+    rainbow (3.1.1)
     rake (13.0.1)
-    regexp_parser (2.1.1)
+    regexp_parser (2.8.1)
     reverse_markdown (2.0.0)
       nokogiri
-    rexml (3.2.5)
+    rexml (3.2.6)
     rspec (3.10.0)
       rspec-core (~> 3.10.0)
       rspec-expectations (~> 3.10.0)
@@ -53,7 +55,7 @@ GEM
     rubocop-performance (1.8.1)
       rubocop (>= 0.87.0)
       rubocop-ast (>= 0.4.0)
-    ruby-progressbar (1.11.0)
+    ruby-progressbar (1.13.0)
     simplecov (0.19.1)
       docile (~> 1.1)
       simplecov-html (~> 0.11)
@@ -93,4 +95,4 @@ DEPENDENCIES
   yard
 
 BUNDLED WITH
-   2.2.29
+   2.3.9
diff --git a/README.md b/README.md
index a9e8530..eaf38db 100644
--- a/README.md
+++ b/README.md
@@ -46,7 +46,7 @@ Then, add the required and optional fields
 class User
   extend EzAttributes
 
-  # Here name and age are required, and email has a default value, so it is optional.
+  # Here, `name` and `age` are required, and `email` has a default value, so it is optional.
   attributes :name, :age, email: 'guest@user.com'
 end
 
@@ -74,7 +74,6 @@ u = User.new(name: 'Matz', age: 22)
 
 u.name
 # NoMethodError (undefined method `name' for #<User:0x000055bac152f130>)
-
 ```
 
 ## Development
diff --git a/ez_attributes.gemspec b/ez_attributes.gemspec
index 567abb0..1e29a66 100644
--- a/ez_attributes.gemspec
+++ b/ez_attributes.gemspec
@@ -12,7 +12,7 @@ Gem::Specification.new do |spec|
   spec.description = "Easily define initializers with keyword args. It supports required and optional args."
   spec.homepage = "https://github.com/MatheusRich/ez_attributes.git"
   spec.license = "MIT"
-  spec.required_ruby_version = Gem::Requirement.new(">= 2.5.0")
+  spec.required_ruby_version = Gem::Requirement.new(">= 3.0.0")
 
   spec.metadata["homepage_uri"] = spec.homepage
   spec.metadata["source_code_uri"] = spec.homepage