diff --git a/lib/vault/client.rb b/lib/vault/client.rb
index 8b25aa3..836aca3 100644
--- a/lib/vault/client.rb
+++ b/lib/vault/client.rb
@@ -38,9 +38,8 @@ class Client
 
     # The default list of options to use when parsing JSON.
     JSON_PARSE_OPTIONS = {
-      max_nesting:      false,
-      create_additions: false,
-      symbolize_names:  true,
+      max_nesting:     false,
+      symbolize_names: true,
     }.freeze
 
     RESCUED_EXCEPTIONS = [].tap do |a|
@@ -385,7 +384,7 @@ def to_query_string(hash)
     #   the parsed response, as an object
     def success(response)
       if response.body && (response.content_type || '').include?("json")
-        JSON.parse(response.body, JSON_PARSE_OPTIONS)
+        JSON.parse(response.body, **JSON_PARSE_OPTIONS)
       else
         response.body
       end
@@ -419,7 +418,7 @@ def error(response)
       if (response.content_type || '').include?("json")
         # Attempt to parse the error as JSON
         begin
-          json = JSON.parse(response.body, JSON_PARSE_OPTIONS)
+          json = JSON.parse(response.body, **JSON_PARSE_OPTIONS)
 
           if json[:errors]
             raise klass.new(address, response, json[:errors])
diff --git a/spec/unit/client_spec.rb b/spec/unit/client_spec.rb
index b94460d..614f1d9 100644
--- a/spec/unit/client_spec.rb
+++ b/spec/unit/client_spec.rb
@@ -113,6 +113,28 @@ module Vault
       end
     end
 
+    describe "JSON response parsing" do
+      before { subject.address = "https://vault.test" }
+
+      it "parses a JSON success response body with symbolized keys" do
+        stub_request(:get, "https://vault.test/")
+          .to_return(status: 200, body: '{"foo":"bar","nested":{"baz":1}}',
+                     headers: { "Content-Type" => "application/json" })
+
+        expect(subject.get("/")).to eq(foo: "bar", nested: { baz: 1 })
+      end
+
+      it "raises an HTTPClientError with the errors parsed from a JSON error response body" do
+        stub_request(:get, "https://vault.test/")
+          .to_return(status: 400, body: '{"errors":["boom"]}',
+                     headers: { "Content-Type" => "application/json" })
+
+        expect {
+          subject.get("/")
+        }.to raise_error(Vault::HTTPClientError) { |error| expect(error.errors).to eq(["boom"]) }
+      end
+    end
+
     context "#with_retries" do
       let(:options) do
         {