diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 2a20a45..6c59c95 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -12,7 +12,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["3.0", "3.1", "3.2", "3.3"]
+        ruby: ["3.2", "3.3", "3.4", "4.0"]
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v3
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index c32c4d2..52bd3c1 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -11,10 +11,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v3
-    - name: Set up Ruby 3.1.4
+    - name: Set up Ruby
       uses: ruby/setup-ruby@v1
       with:
-        ruby-version: "3.1.4"
+        ruby-version: "3.2.0"
 
     - name: Build and test
       run: |
diff --git a/Gemfile.lock b/Gemfile.lock
index d252696..b585437 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,134 +1,176 @@
 PATH
   remote: .
   specs:
-    maremma (5.0.0)
-      activesupport (>= 4.2.5)
-      addressable (>= 2.3.6)
+    maremma (6.0.0)
+      activesupport (~> 8.1, >= 8.1.2)
+      addressable (~> 2.8, >= 2.8.9)
       builder (~> 3.2, >= 3.2.2)
-      excon (~> 0.71.0)
+      excon (~> 1.3, >= 1.3.2)
       faraday (>= 2.0)
-      faraday-encoding (~> 0.0.5)
-      faraday-excon (~> 2.1.0)
-      faraday-follow_redirects (~> 0.3.0)
-      faraday-gzip (~> 0.1.0)
-      faraday-multipart (~> 1.0.4)
-      nokogiri (~> 1.16, >= 1.16.2)
-      oj (>= 2.8.3)
+      faraday-encoding (~> 0.0.6)
+      faraday-excon (~> 2.4.0)
+      faraday-follow_redirects (~> 0.5.0)
+      faraday-gzip (~> 3.1.0)
+      faraday-multipart (~> 1.2.0)
+      nokogiri (~> 1.19, >= 1.19.1)
+      oj (~> 3.16, >= 3.16.15)
       oj_mimic_json (~> 1.0, >= 1.0.1)
 
 GEM
   remote: https://rubygems.org/
   specs:
-    activesupport (6.1.7)
-      concurrent-ruby (~> 1.0, >= 1.0.2)
+    activesupport (8.1.2)
+      base64
+      bigdecimal
+      concurrent-ruby (~> 1.0, >= 1.3.1)
+      connection_pool (>= 2.2.5)
+      drb
       i18n (>= 1.6, < 2)
+      json
+      logger (>= 1.4.2)
       minitest (>= 5.1)
-      tzinfo (~> 2.0)
-      zeitwerk (~> 2.3)
-    addressable (2.8.1)
-      public_suffix (>= 2.0.2, < 6.0)
-    ast (2.4.2)
+      securerandom (>= 0.3)
+      tzinfo (~> 2.0, >= 2.0.5)
+      uri (>= 0.13.1)
+    addressable (2.8.9)
+      public_suffix (>= 2.0.2, < 8.0)
+    ast (2.4.3)
+    base64 (0.3.0)
+    bigdecimal (4.0.1)
     builder (3.2.4)
-    concurrent-ruby (1.1.10)
-    crack (0.4.5)
+    concurrent-ruby (1.3.6)
+    connection_pool (3.0.2)
+    crack (1.0.1)
+      bigdecimal
       rexml
-    diff-lcs (1.5.0)
-    docile (1.4.0)
-    excon (0.71.1)
-    faraday (2.6.0)
-      faraday-net_http (>= 2.0, < 3.1)
-      ruby2_keywords (>= 0.0.4)
-    faraday-encoding (0.0.5)
+    diff-lcs (1.6.2)
+    docile (1.4.1)
+    drb (2.2.3)
+    excon (1.4.0)
+      logger
+    faraday (2.14.1)
+      faraday-net_http (>= 2.0, < 3.5)
+      json
+      logger
+    faraday-encoding (0.0.6)
       faraday
-    faraday-excon (2.1.0)
-      excon (>= 0.27.4)
-      faraday (~> 2.0)
-    faraday-follow_redirects (0.3.0)
+    faraday-excon (2.4.0)
+      excon (>= 1.0.0)
+      faraday (>= 2.11.0, < 3)
+    faraday-follow_redirects (0.5.0)
       faraday (>= 1, < 3)
-    faraday-gzip (0.1.0)
-      faraday (>= 1.0)
-      zlib (~> 2.1)
-    faraday-multipart (1.0.4)
-      multipart-post (~> 2)
+    faraday-gzip (3.1.0)
+      faraday (>= 2.0, < 3)
+      zlib (~> 3.0)
+    faraday-multipart (1.2.0)
+      multipart-post (~> 2.0)
     faraday-net_http (3.0.1)
-    hashdiff (1.0.1)
+    hashdiff (1.2.1)
     i18n (1.12.0)
       concurrent-ruby (~> 1.0)
-    jaro_winkler (1.5.4)
+    json (2.18.1)
+    json-schema (6.1.0)
+      addressable (~> 2.8)
+      bigdecimal (>= 3.1, < 5)
+    language_server-protocol (3.17.0.5)
+    lint_roller (1.1.0)
+    logger (1.7.0)
+    mcp (0.7.1)
+      json-schema (>= 4.1)
     mini_portile2 (2.8.5)
-    minitest (5.16.3)
+    minitest (6.0.2)
+      drb (~> 2.0)
+      prism (~> 1.5)
     multipart-post (2.2.3)
-    nokogiri (1.16.2)
+    nokogiri (1.19.1)
       mini_portile2 (~> 2.8.2)
       racc (~> 1.4)
-    oj (3.13.21)
+    oj (3.16.15)
+      bigdecimal (>= 3.0)
+      ostruct (>= 0.2)
     oj_mimic_json (1.0.1)
-    parallel (1.22.1)
-    parser (3.1.2.1)
+    ostruct (0.6.3)
+    parallel (1.27.0)
+    parser (3.3.10.2)
       ast (~> 2.4.1)
+      racc
+    prism (1.9.0)
     public_suffix (5.0.0)
     racc (1.6.0)
-    rack (2.2.6.4)
-    rack-test (0.8.3)
-      rack (>= 1.0, < 3)
+    rack (3.2.5)
+    rack-test (2.2.0)
+      rack (>= 1.3)
     rainbow (3.1.1)
-    rake (13.0.6)
-    rexml (3.2.5)
-    rspec (3.11.0)
-      rspec-core (~> 3.11.0)
-      rspec-expectations (~> 3.11.0)
-      rspec-mocks (~> 3.11.0)
-    rspec-core (3.11.0)
-      rspec-support (~> 3.11.0)
-    rspec-expectations (3.11.1)
+    rake (13.3.1)
+    regexp_parser (2.11.3)
+    rexml (3.4.4)
+    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 (~> 3.11.0)
-    rspec-mocks (3.11.1)
+      rspec-support (~> 3.13.0)
+    rspec-mocks (3.13.8)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.11.0)
-    rspec-support (3.11.1)
-    rubocop (0.77.0)
-      jaro_winkler (~> 1.5.1)
+      rspec-support (~> 3.13.0)
+    rspec-support (3.13.7)
+    rubocop (1.85.0)
+      json (~> 2.3)
+      language_server-protocol (~> 3.17.0.2)
+      lint_roller (~> 1.1.0)
+      mcp (~> 0.6)
       parallel (~> 1.10)
-      parser (>= 2.6)
+      parser (>= 3.3.0.2)
       rainbow (>= 2.2.2, < 4.0)
+      regexp_parser (>= 2.9.3, < 3.0)
+      rubocop-ast (>= 1.49.0, < 2.0)
       ruby-progressbar (~> 1.7)
-      unicode-display_width (>= 1.4.0, < 1.7)
-    rubocop-performance (1.6.1)
-      rubocop (>= 0.71.0)
-    ruby-progressbar (1.11.0)
-    ruby2_keywords (0.0.5)
-    simplecov (0.21.2)
+      unicode-display_width (>= 2.4.0, < 4.0)
+    rubocop-ast (1.49.0)
+      parser (>= 3.3.7.2)
+      prism (~> 1.7)
+    rubocop-performance (1.26.1)
+      lint_roller (~> 1.1)
+      rubocop (>= 1.75.0, < 2.0)
+      rubocop-ast (>= 1.47.1, < 2.0)
+    ruby-progressbar (1.13.0)
+    securerandom (0.4.1)
+    simplecov (0.22.0)
       docile (~> 1.1)
       simplecov-html (~> 0.11)
       simplecov_json_formatter (~> 0.1)
-    simplecov-html (0.12.3)
+    simplecov-html (0.13.2)
     simplecov_json_formatter (0.1.4)
     tzinfo (2.0.5)
       concurrent-ruby (~> 1.0)
-    unicode-display_width (1.6.1)
-    vcr (3.0.3)
-    webmock (3.18.1)
+    unicode-display_width (3.2.0)
+      unicode-emoji (~> 4.1)
+    unicode-emoji (4.2.0)
+    uri (1.1.1)
+    vcr (6.4.0)
+    webmock (3.26.1)
       addressable (>= 2.8.0)
       crack (>= 0.3.2)
       hashdiff (>= 0.4.0, < 2.0.0)
-    zeitwerk (2.6.1)
-    zlib (2.1.1)
+    zlib (3.2.2)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
-  bundler (~> 2.0)
+  bundler (~> 2.5.5)
   maremma!
-  rack-test (~> 0)
-  rake
-  rspec (~> 3.4)
-  rubocop (~> 0.77.0)
-  rubocop-performance (~> 1.5, >= 1.5.1)
-  simplecov
-  vcr (~> 3.0, >= 3.0.3)
-  webmock (~> 3.0, >= 3.0.1)
+  rack-test (~> 2.2)
+  rake (~> 13.3, >= 13.3.1)
+  rspec (~> 3.13, >= 3.13.2)
+  rubocop (~> 1.85)
+  rubocop-performance (~> 1.26, >= 1.26.1)
+  simplecov (~> 0.22.0)
+  vcr (~> 6.4)
+  webmock (~> 3.26, >= 3.26.1)
 
 BUNDLED WITH
    2.5.5
diff --git a/lib/maremma/version.rb b/lib/maremma/version.rb
index f1fe632..fb9f632 100644
--- a/lib/maremma/version.rb
+++ b/lib/maremma/version.rb
@@ -1,3 +1,3 @@
 module Maremma
-  VERSION = "5.0.0".freeze
+  VERSION = "6.0.0".freeze
 end
diff --git a/maremma.gemspec b/maremma.gemspec
index 29c03c7..072251a 100644
--- a/maremma.gemspec
+++ b/maremma.gemspec
@@ -13,32 +13,32 @@ Gem::Specification.new do |s|
   s.version       = Maremma::VERSION
   s.extra_rdoc_files = ["README.md"]
   s.license       = "MIT"
-  s.required_ruby_version = ['>=2.3']
+  s.required_ruby_version = ['>=3.2.0']
 
   s.files         = `git ls-files`.split("\n")
   s.test_files    = `git ls-files -- {test,spec,features}/*`.split("\n")
 
   # Declary dependencies here, rather than in the Gemfile
-  s.add_dependency "activesupport", ">= 4.2.5"
-  s.add_dependency "addressable", ">= 2.3.6"
+  s.add_dependency "activesupport", "~> 8.1", ">= 8.1.2"
+  s.add_dependency "addressable", "~> 2.8", ">= 2.8.9"
   s.add_dependency "builder", "~> 3.2", ">= 3.2.2"
-  s.add_dependency "excon", "~> 0.71.0"
+  s.add_dependency "excon", "~> 1.3", ">= 1.3.2"
   s.add_dependency "faraday", ">=2.0"
-  s.add_dependency "faraday-follow_redirects", "~> 0.3.0"
-  s.add_dependency "faraday-encoding", "~> 0.0.5"
-  s.add_dependency "faraday-excon", "~>2.1.0"
-  s.add_dependency "faraday-gzip", "~> 0.1.0"
-  s.add_dependency "faraday-multipart", "~> 1.0.4"
-  s.add_dependency "nokogiri", "~> 1.16", ">= 1.16.2"
-  s.add_dependency "oj", ">= 2.8.3"
+  s.add_dependency "faraday-follow_redirects", "~> 0.5.0"
+  s.add_dependency "faraday-encoding", "~> 0.0.6"
+  s.add_dependency "faraday-excon", "~>2.4.0"
+  s.add_dependency "faraday-gzip", "~> 3.1.0"
+  s.add_dependency "faraday-multipart", "~> 1.2.0"
+  s.add_dependency "nokogiri", "~> 1.19", ">= 1.19.1"
+  s.add_dependency "oj", "~> 3.16", ">= 3.16.15"
   s.add_dependency "oj_mimic_json", "~> 1.0", ">= 1.0.1"
-  s.add_development_dependency "bundler", "~> 2.0"
-  s.add_development_dependency "rack-test", "~> 0"
-  s.add_development_dependency "rake"
-  s.add_development_dependency "rspec", "~> 3.4"
-  s.add_development_dependency "rubocop", "~> 0.77.0"
-  s.add_development_dependency "rubocop-performance", "~> 1.5", ">= 1.5.1"
-  s.add_development_dependency "simplecov"
-  s.add_development_dependency "vcr", "~> 3.0", ">= 3.0.3"
-  s.add_development_dependency "webmock", "~> 3.0", ">= 3.0.1"
+  s.add_development_dependency "bundler", "~> 2.5.5"
+  s.add_development_dependency "rack-test", "~> 2.2"
+  s.add_development_dependency "rake", "~> 13.3", ">= 13.3.1"
+  s.add_development_dependency "rspec", "~> 3.13", ">= 3.13.2"
+  s.add_development_dependency "rubocop", "~> 1.85"
+  s.add_development_dependency "rubocop-performance", "~> 1.26", ">= 1.26.1"
+  s.add_development_dependency "simplecov", "~> 0.22.0"
+  s.add_development_dependency "vcr", "~> 6.4"
+  s.add_development_dependency "webmock", "~> 3.26", ">= 3.26.1"
 end
diff --git a/spec/maremma_spec.rb b/spec/maremma_spec.rb
index f13fcdc..85ab01f 100644
--- a/spec/maremma_spec.rb
+++ b/spec/maremma_spec.rb
@@ -96,8 +96,8 @@
     it "get utf8 bad encoding", vcr: true do
       response = subject.get("https://pub.sandbox.orcid.org/v3.0/0000-0002-5721-4355", accept: "json")
       expect(response.body["data"]).to be_a(Hash)
-      expect(response.body["data"]["person"]["name"]["given-names"]["value"]).to eq("DataC??t??")
-      expect(response.body["data"]["person"]["name"]["family-name"]["value"]).to eq("UTF8 T??st")
+      expect(response.body["data"]["person"]["name"]["given-names"]["value"]).to eq("DataCíté")
+      expect(response.body["data"]["person"]["name"]["family-name"]["value"]).to eq("UTF8 Tést")
     end
 
     it "get utf8 skip encoding", vcr: true do
@@ -113,7 +113,7 @@
       stub = stub_request(:head, url).to_return(status: 200, headers: { "Content-Type" => "text/html" })
       response = subject.head(url, accept: "html")
       expect(response.body).to be_nil
-      expect(response.headers).to eq("Content-Length" => 0, "Content-Type" => "text/html")
+      expect(response.headers).to eq("Content-Type" => "text/html")
       expect(stub).to have_been_requested
     end
   end
@@ -165,7 +165,7 @@
       stub = stub_request(:get, url).to_return(body: nil, status: 200, headers: { "Content-Type" => "application/json" })
       response = subject.get(url)
       expect(response.body).to eq("data" => nil)
-      expect(response.headers).to eq("Content-Length" => 0, "Content-Type" => "application/json")
+      expect(response.headers).to eq("Content-Type" => "application/json")
       expect(stub).to have_been_requested
     end
 
@@ -173,7 +173,7 @@
       stub = stub_request(:get, url).to_return(body: nil, status: 200, headers: { "Content-Type" => "application/xml" })
       response = subject.get(url, accept: "xml")
       expect(response.body).to eq("data" => nil)
-      expect(response.headers).to eq("Content-Length" => 0, "Content-Type" => "application/xml")
+      expect(response.headers).to eq("Content-Type" => "application/xml")
       expect(stub).to have_been_requested
     end
 
@@ -181,7 +181,7 @@
       stub = stub_request(:get, url).to_return(body: nil, status: 200, headers: { "Content-Type" => "text/html" })
       response = subject.get(url, accept: "html")
       expect(response.body).to eq("data" => nil)
-      expect(response.headers).to eq("Content-Length" => 0, "Content-Type" => "text/html")
+      expect(response.headers).to eq("Content-Type" => "text/html")
       expect(stub).to have_been_requested
     end
 
@@ -333,7 +333,7 @@
       stub = stub_request(:delete, url).to_return(status: 204, headers: { "Content-Type" => "text/html" })
       response = subject.delete(url)
       expect(response.body).to eq("data" => nil)
-      expect(response.headers).to eq("Content-Length" => 0, "Content-Type" => "text/html")
+      expect(response.headers).to eq("Content-Type" => "text/html")
       expect(response.status).to eq(204)
       expect(stub).to have_been_requested
     end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index ff8cf17..6507dc5 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -6,6 +6,7 @@
 require "simplecov"
 SimpleCov.start
 
+require "ostruct"
 require "maremma"
 require "rspec"
 require "rack/test"