diff --git a/dm-types.gemspec b/dm-types.gemspec
index 52e296f..9fe8c6a 100644
--- a/dm-types.gemspec
+++ b/dm-types.gemspec
@@ -15,10 +15,16 @@ Gem::Specification.new do |gem|
   gem.require_paths = [ "lib" ]
   gem.version       = '1.2.2'
 
+  # Ruby 3.3 compatibility: the original 1.2.2 gemspec pinned json (~> 1.6) and
+  # fastercsv (~> 1.5), both unmaintained and incompatible with Ruby 3.x:
+  #   * json 1.8.x fails to resolve cleanly against the modern default json gem
+  #     and forces json_pure 1.8.6 into the bundle (broken on Ruby 3.2+).
+  #   * fastercsv targets Ruby 1.8 only; Ruby 1.9+ ships csv in the stdlib.
+  # The runtime never uses these directly: json.rb uses multi_json, and csv.rb
+  # `require 'csv'` (stdlib) first, only falling back to fastercsv on Ruby < 1.9.
+  # Drop both pins so the bundle can use multi_json + the modern default json gem.
   gem.add_runtime_dependency('bcrypt-ruby', '~> 3.0')
-  gem.add_runtime_dependency('fastercsv',   '~> 1.5')
   gem.add_runtime_dependency('multi_json',  '~> 1.0')
-  gem.add_runtime_dependency('json',        '~> 1.6')
   gem.add_runtime_dependency('stringex',    '~> 1.4')
   gem.add_runtime_dependency('uuidtools',   '~> 2.1')
   gem.add_runtime_dependency('dm-core',     '~> 1.2.0')
diff --git a/lib/dm-types/enum.rb b/lib/dm-types/enum.rb
index 256f1fb..86e025b 100644
--- a/lib/dm-types/enum.rb
+++ b/lib/dm-types/enum.rb
@@ -41,7 +41,10 @@ def typecast_to_primitive(value)
         case flag_map[1]
         when ::Symbol then value.to_sym
         when ::String then value.to_s
-        when ::Fixnum then value.to_i
+        # Fixnum was unified into Integer in Ruby 2.4 and the constant was
+        # removed in Ruby 3.2; match ::Integer so this `when` clause keeps
+        # working (every former Fixnum is an Integer).
+        when ::Integer then value.to_i
         else               value
         end
       end