diff --git a/CHANGELOG.md b/CHANGELOG.md
index 87bfd21..5f282ea 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## [0.3.0] - 2024-01-27
+
+- use sinatra >= 4.0.0
+
 ## [0.2.0] - 2023-07-30
 
 - use ruby.wasm 2.0.0
diff --git a/gem/Gemfile.lock b/gem/Gemfile.lock
index 91fe911..dca18a5 100644
--- a/gem/Gemfile.lock
+++ b/gem/Gemfile.lock
@@ -1,11 +1,11 @@
 PATH
   remote: .
   specs:
-    bormashino (0.2.0)
+    bormashino (0.3.0)
       json_pure (~> 2.6, >= 2.6.1)
       os (~> 1.1, >= 1.1.4)
       ruby2_keywords (= 0.0.4)
-      sinatra (~> 2.2)
+      sinatra (>= 4.0.0)
 
 GEM
   remote: https://rubygems.org/
@@ -16,6 +16,7 @@ GEM
       minitest (>= 5.1)
       tzinfo (~> 2.0)
     ast (2.4.2)
+    base64 (0.2.0)
     coderay (1.1.3)
     concurrent-ruby (1.2.2)
     diff-lcs (1.5.0)
@@ -52,7 +53,7 @@ GEM
     lumberjack (1.2.8)
     method_source (1.0.0)
     minitest (5.19.0)
-    mustermann (2.0.2)
+    mustermann (3.0.0)
       ruby2_keywords (~> 0.0.1)
     nenv (0.3.0)
     notiffany (0.1.3)
@@ -65,9 +66,12 @@ GEM
     pry (0.14.2)
       coderay (~> 1.1)
       method_source (~> 1.0)
-    rack (2.2.7)
-    rack-protection (2.2.4)
-      rack
+    rack (3.0.8)
+    rack-protection (4.0.0)
+      base64 (>= 0.1.0)
+      rack (>= 3.0.0, < 4)
+    rack-session (2.0.0)
+      rack (>= 3.0.0)
     rainbow (3.1.1)
     rake (13.0.6)
     rb-fsevent (0.11.2)
@@ -117,13 +121,14 @@ GEM
     ruby-progressbar (1.13.0)
     ruby2_keywords (0.0.4)
     shellany (0.0.1)
-    sinatra (2.2.4)
-      mustermann (~> 2.0)
-      rack (~> 2.2)
-      rack-protection (= 2.2.4)
+    sinatra (4.0.0)
+      mustermann (~> 3.0)
+      rack (>= 3.0.0, < 4)
+      rack-protection (= 4.0.0)
+      rack-session (>= 2.0.0, < 3)
       tilt (~> 2.0)
     thor (1.2.2)
-    tilt (2.1.0)
+    tilt (2.3.0)
     tzinfo (2.0.6)
       concurrent-ruby (~> 1.0)
     unicode-display_width (2.4.2)
diff --git a/gem/bormashino.gemspec b/gem/bormashino.gemspec
index 63f8833..3240a99 100644
--- a/gem/bormashino.gemspec
+++ b/gem/bormashino.gemspec
@@ -28,7 +28,7 @@ Gem::Specification.new do |spec|
   # Uncomment to register a new dependency of your gem
   # spec.add_dependency "example-gem", "~> 1.0"
   spec.add_dependency 'json_pure', '~> 2.6', '>= 2.6.1'
-  spec.add_dependency 'sinatra', '~> 2.2'
+  spec.add_dependency 'sinatra', '>= 4.0.0'
   spec.add_dependency 'ruby2_keywords', '0.0.4'
   spec.add_dependency 'os', '~> 1.1', '>= 1.1.4'
 
diff --git a/gem/lib/bormashino/version.rb b/gem/lib/bormashino/version.rb
index 3c2d64f..7000648 100644
--- a/gem/lib/bormashino/version.rb
+++ b/gem/lib/bormashino/version.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module Bormashino
-  VERSION = '0.2.0'
+  VERSION = '0.3.0'
 end
diff --git a/gem/spec/bormashino/server_spec.rb b/gem/spec/bormashino/server_spec.rb
index dbaf475..d4f39e7 100644
--- a/gem/spec/bormashino/server_spec.rb
+++ b/gem/spec/bormashino/server_spec.rb
@@ -171,7 +171,7 @@ class MockApp < Sinatra::Base
 
       it 'sends referer' do
         expect(subject.first).to eq 302
-        expect(subject[1]['Location']).to eq 'http://example.com:0/referer'
+        expect(subject[1]['location']).to eq 'http://example.com:0/referer'
       end
     end
   end
diff --git a/npm/package-lock.json b/npm/package-lock.json
index 1b7d222..f4178ba 100644
--- a/npm/package-lock.json
+++ b/npm/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "bormashino",
-  "version": "0.2.0",
+  "version": "0.3.0",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
     "": {
       "name": "bormashino",
-      "version": "0.2.0",
+      "version": "0.3.0",
       "license": "MIT",
       "dependencies": {
         "@wasmer/wasi": "0.12.0",
diff --git a/npm/package.json b/npm/package.json
index 75c29ac..1633692 100644
--- a/npm/package.json
+++ b/npm/package.json
@@ -2,7 +2,7 @@
   "name": "bormashino",
   "description": "The package to build SPAs with Ruby",
   "homepage": "https://github.com/keyasuda/bormashino",
-  "version": "0.2.0",
+  "version": "0.3.0",
   "main": "src/index.js",
   "scripts": {
     "test": "jest --notify src/",
diff --git a/npm/src/applyServerResult.js b/npm/src/applyServerResult.js
index 09e58cb..e1dd460 100644
--- a/npm/src/applyServerResult.js
+++ b/npm/src/applyServerResult.js
@@ -41,13 +41,13 @@ export const applyServerResult = (src, target, router) => {
       return true
 
     case 302:
-      const loc = new URL(src[1]['Location'])
+      const loc = new URL(src[1]['location'])
 
       if (loc.host == 'example.com:0') {
         const path = loc.pathname + loc.search
         router.pushState(path)
       } else {
-        location.href = src[1]['Location']
+        location.href = src[1]['location']
       }
       return false
 
diff --git a/npm/src/applyServerResult.test.js b/npm/src/applyServerResult.test.js
index b2d9d9e..f84ecde 100644
--- a/npm/src/applyServerResult.test.js
+++ b/npm/src/applyServerResult.test.js
@@ -110,7 +110,7 @@ describe('applyServerResult', () => {
 
   describe('302 relative location', () => {
     beforeEach(() => {
-      content = [302, { Location: 'http://example.com:0/location' }, []]
+      content = [302, { location: 'http://example.com:0/location' }, []]
       ret = applyServerResult(content, target, router)
     })
 
@@ -132,13 +132,13 @@ describe('applyServerResult', () => {
       delete window.location
       window.location = { assign: jest.fn() }
 
-      content = [302, { Location: 'http://absolute.example.com/location' }, []]
+      content = [302, { location: 'http://absolute.example.com/location' }, []]
 
       ret = applyServerResult(content, target, router)
     })
 
     it('navigates to the location', () => {
-      expect(location.href).toEqual(content[1]['Location'])
+      expect(location.href).toEqual(content[1]['location'])
     })
 
     it('returns true', () => {
diff --git a/test-app/Gemfile.lock b/test-app/Gemfile.lock
index 958716a..001ac9f 100644
--- a/test-app/Gemfile.lock
+++ b/test-app/Gemfile.lock
@@ -11,11 +11,11 @@ GIT
 PATH
   remote: ../gem
   specs:
-    bormashino (0.2.0)
+    bormashino (0.3.0)
       json_pure (~> 2.6, >= 2.6.1)
       os (~> 1.1, >= 1.1.4)
       ruby2_keywords (= 0.0.4)
-      sinatra (~> 2.2)
+      sinatra (>= 4.0.0)
 
 GEM
   remote: https://rubygems.org/
@@ -28,6 +28,7 @@ GEM
     addressable (2.8.4)
       public_suffix (>= 2.0.2, < 6.0)
     ast (2.4.2)
+    base64 (0.2.0)
     capybara (3.39.1)
       addressable
       matrix
@@ -92,7 +93,7 @@ GEM
     method_source (1.0.0)
     mini_mime (1.1.2)
     minitest (5.19.0)
-    mustermann (2.0.2)
+    mustermann (3.0.0)
       ruby2_keywords (~> 0.0.1)
     nenv (0.3.0)
     nokogiri (1.15.1-x86_64-linux)
@@ -109,9 +110,12 @@ GEM
       method_source (~> 1.0)
     public_suffix (5.0.1)
     racc (1.6.2)
-    rack (2.2.7)
-    rack-protection (2.2.4)
-      rack
+    rack (3.0.8)
+    rack-protection (4.0.0)
+      base64 (>= 0.1.0)
+      rack (>= 3.0.0, < 4)
+    rack-session (2.0.0)
+      rack (>= 3.0.0)
     rack-test (2.1.0)
       rack (>= 1.3)
     rainbow (3.1.1)
@@ -163,13 +167,14 @@ GEM
     ruby-progressbar (1.13.0)
     ruby2_keywords (0.0.4)
     shellany (0.0.1)
-    sinatra (2.2.4)
-      mustermann (~> 2.0)
-      rack (~> 2.2)
-      rack-protection (= 2.2.4)
+    sinatra (4.0.0)
+      mustermann (~> 3.0)
+      rack (>= 3.0.0, < 4)
+      rack-protection (= 4.0.0)
+      rack-session (>= 2.0.0, < 3)
       tilt (~> 2.0)
     thor (1.2.2)
-    tilt (2.1.0)
+    tilt (2.3.0)
     tzinfo (2.0.6)
       concurrent-ruby (~> 1.0)
     unicode-display_width (2.4.2)
diff --git a/test-app/package-lock.json b/test-app/package-lock.json
index 2c0d7a7..4354d29 100644
--- a/test-app/package-lock.json
+++ b/test-app/package-lock.json
@@ -1,5 +1,5 @@
 {
-  "name": "npm-proj-1706207272237-0.5249562090028224nqODAi",
+  "name": "test-app",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
@@ -15,18 +15,18 @@
     },
     "../npm": {
       "name": "bormashino",
-      "version": "0.2.0",
+      "version": "0.3.0",
       "license": "MIT",
       "dependencies": {
         "@wasmer/wasi": "0.12.0",
         "@wasmer/wasmfs": "^0.12.0",
         "html5-history-router": "^1.1.0",
-        "ruby-3_2-wasm-wasi": "2.0.0"
+        "ruby-3_2-wasm-wasi": "2.3.0"
       },
       "devDependencies": {
-        "@babel/core": "^7.21.8",
-        "@babel/preset-env": "^7.21.5",
-        "jest": "^28.1.3",
+        "@babel/core": "^7.23.6",
+        "@babel/preset-env": "^7.23.6",
+        "jest": "^29.7.0",
         "jest-environment-jsdom": "^28.1.3",
         "node-notifier": "^10.0.1"
       }
@@ -5011,15 +5011,15 @@
     "bormashino": {
       "version": "file:../npm",
       "requires": {
-        "@babel/core": "^7.21.8",
-        "@babel/preset-env": "^7.21.5",
+        "@babel/core": "^7.23.6",
+        "@babel/preset-env": "^7.23.6",
         "@wasmer/wasi": "0.12.0",
         "@wasmer/wasmfs": "^0.12.0",
         "html5-history-router": "^1.1.0",
-        "jest": "^28.1.3",
+        "jest": "^29.7.0",
         "jest-environment-jsdom": "^28.1.3",
         "node-notifier": "^10.0.1",
-        "ruby-3_2-wasm-wasi": "2.0.0"
+        "ruby-3_2-wasm-wasi": "2.3.0"
       }
     },
     "braces": {
diff --git a/test-app/spec/spec_helper.rb b/test-app/spec/spec_helper.rb
index a870fd1..ce9df6c 100644
--- a/test-app/spec/spec_helper.rb
+++ b/test-app/spec/spec_helper.rb
@@ -9,7 +9,7 @@ class JSConsoleLogger
   def puts(log)
     src = log.strip.sub(/\A.+[ 0-9.▶◀]+\{/, '{')
     src = JSON.parse(src)
-    $stdout.puts src['params']['args'].map { |a| a['value'] } if src['method'] == 'Runtime.consoleAPICalled'
+    $stdout.puts src['params']['args'].pluck('value') if src['method'] == 'Runtime.consoleAPICalled'
   rescue StandardError
     # do nothing
   end
diff --git a/test-app/spec/test_app_spec.rb b/test-app/spec/test_app_spec.rb
index 6eab862..3da3bc8 100644
--- a/test-app/spec/test_app_spec.rb
+++ b/test-app/spec/test_app_spec.rb
@@ -1,4 +1,4 @@
-RSpec.describe 'test_app', type: :feature, retry: 10 do
+RSpec.describe 'test_app', retry: 10, type: :feature do
   subject { page }
 
   before do
diff --git a/test-app/src/Gemfile.lock b/test-app/src/Gemfile.lock
index 755b6c3..222605a 100644
--- a/test-app/src/Gemfile.lock
+++ b/test-app/src/Gemfile.lock
@@ -1,19 +1,24 @@
 GEM
   remote: https://rubygems.org/
   specs:
+    base64 (0.2.0)
     json_pure (2.6.3)
     mustermann (3.0.0)
       ruby2_keywords (~> 0.0.1)
-    rack (2.2.7)
-    rack-protection (3.0.6)
-      rack
+    rack (3.0.8)
+    rack-protection (4.0.0)
+      base64 (>= 0.1.0)
+      rack (>= 3.0.0, < 4)
+    rack-session (2.0.0)
+      rack (>= 3.0.0)
     ruby2_keywords (0.0.4)
-    sinatra (3.0.6)
+    sinatra (4.0.0)
       mustermann (~> 3.0)
-      rack (~> 2.2, >= 2.2.4)
-      rack-protection (= 3.0.6)
+      rack (>= 3.0.0, < 4)
+      rack-protection (= 4.0.0)
+      rack-session (>= 2.0.0, < 3)
       tilt (~> 2.0)
-    tilt (2.1.0)
+    tilt (2.3.0)
 
 PLATFORMS
   ruby