diff --git a/Gemfile b/Gemfile
index 8c93a7b..4c96862 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,3 +1,13 @@
 source 'http://rubygems.org'
 # See json_csv.gemspec for dependency info
 gemspec
+
+gem "rake", "~> 13.0"
+
+gem "rspec", "~> 3.12"
+
+gem "rubocop", "~> 0.51.0"
+
+gem "rubocop-rspec", "~> 1.20"
+
+gem "simplecov", "~> 0.22.0"
diff --git a/json_csv.gemspec b/json_csv.gemspec
index 027ae78..72c90c8 100644
--- a/json_csv.gemspec
+++ b/json_csv.gemspec
@@ -12,12 +12,6 @@ Gem::Specification.new do |s|
   s.homepage    = 'https://github.com/cul/json_csv'
   s.license     = 'MIT'
 
-  s.add_development_dependency("rake", ">= 10.1")
-  s.add_development_dependency("rspec", "~>3.7")
-  s.add_development_dependency("rubocop", "~> 0.51.0")
-  s.add_development_dependency("rubocop-rspec", "~> 1.20.1")
-  s.add_development_dependency("simplecov", "~> 0.15.1")
-
   s.files        = Dir["lib/**/*.rb", "lib/tasks/**/*.rake", "bin/*", "LICENSE", "*.md"]
   s.require_paths = ['lib']
 end
diff --git a/lib/json_csv/csv_to_json.rb b/lib/json_csv/csv_to_json.rb
index d5f9f00..831774d 100644
--- a/lib/json_csv/csv_to_json.rb
+++ b/lib/json_csv/csv_to_json.rb
@@ -22,7 +22,7 @@ module ClassMethods
       # Sample usage: csv_file_to_hierarchical_json_hash(path_to_csv, field_casting_rules = {}, strip_value_whitespace = true) do |row_json_hash, row_number|
       def csv_file_to_hierarchical_json_hash(path_to_csv, field_casting_rules = {}, strip_value_whitespace = true)
         i = 2 # start with row 2 because this corresponds to the SECOND row of 1-indexed CSV data (where headers are row 1)
-        CSV.foreach(path_to_csv, headers: true, header_converters: lambda { |header|
+        CSV.foreach(path_to_csv, converters: %i[numeric date], headers: true, header_converters: lambda { |header|
           header.strip # remove leading and trailing header whitespace
         }) do |row_data_hash|
           yield csv_row_hash_to_hierarchical_json_hash(row_data_hash, field_casting_rules, strip_value_whitespace), i
@@ -54,7 +54,7 @@ def put_value_at_json_path(obj, json_path, value, field_casting_rules = {}, full
           # If the full_json_path_from_top matches one of the field_casting_rules,
           # then case this field to the specified cast type
           full_json_path_from_top_as_field_casting_rule_pattern = real_json_path_to_field_casting_rule_pattern(full_json_path_from_top)
-          obj[json_path_pieces[0]] = field_casting_rules.key?(full_json_path_from_top_as_field_casting_rule_pattern) ? apply_field_casting_type(value, field_casting_rules[full_json_path_from_top_as_field_casting_rule_pattern]) : value
+          obj[json_path_pieces[0]] = field_casting_rules.key?(full_json_path_from_top_as_field_casting_rule_pattern) ? apply_field_casting_type(value, field_casting_rules[full_json_path_from_top_as_field_casting_rule_pattern]) : value.to_s
         else
           obj[json_path_pieces[0]] ||= (json_path_pieces[1].is_a?(Integer) ? [] : {})
           put_value_at_json_path(obj[json_path_pieces[0]], pieces_to_json_path(json_path_pieces[1..-1]), value, field_casting_rules, full_json_path_from_top)
@@ -72,10 +72,10 @@ def apply_field_casting_type(value, field_casting_type)
 
         case field_casting_type
         when TYPE_INTEGER
-          raise ArgumentError, "\"#{value}\" is not an integer" unless value =~ /^[0-9]+$/
+          raise ArgumentError, "\"#{value}\" is not an integer" unless value.to_s =~ /^[0-9]+$/
           value.to_i
         when TYPE_FLOAT
-          raise ArgumentError, "\"#{value}\" is not a float" unless value =~ /^[0-9]+(\.[0-9]+)*$/ || value =~ /^\.[0-9]+$/
+          raise ArgumentError, "\"#{value}\" is not a float" unless value.to_s =~ /^[0-9]+(\.[0-9]+)*$/ || value.to_s =~ /^\.[0-9]+$/
           value.to_f
         when TYPE_BOOLEAN
           if value.downcase == 'true'
diff --git a/lib/json_csv/version.rb b/lib/json_csv/version.rb
index 33ae428..2201123 100644
--- a/lib/json_csv/version.rb
+++ b/lib/json_csv/version.rb
@@ -1,6 +1,6 @@
 module JsonCsv
 
-  VERSION = '1.0.0'.freeze
+  VERSION = '1.0.1'.freeze
 
   def self.version
     VERSION
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index b5ee78d..09757d1 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -11,7 +11,7 @@ def absolute_fixture_path(file)
 end
 def fixture(file)
   path = absolute_fixture_path(file)
-  raise "No fixture file at #{path}" unless File.exists? path
+  raise "No fixture file at #{path}" unless File.exist? path
   File.new(path)
 end