diff --git a/demos/AoModel.rb b/demos/AoModel.rb
index d535e54169bf8e9be02c541292e04e9e2da1721c..147283c679aaa2cea03b6d164477ada20fed8e0d 100644
--- a/demos/AoModel.rb
+++ b/demos/AoModel.rb
@@ -1,6 +1,6 @@
 #!/usr/bin/env ruby
 
-require 'rubygems'
+require 'rubygems' if RUBY_VERSION =~ /^1\.8/
 require 'simplekit'
 
 # Demonstration model of Operational Availability (Ao).
@@ -9,13 +9,13 @@ class AoModel
   include SimpleKit
 
   # model state
-  attr_reader  :numAvailableJeeps,
+  attr_reader :numAvailableJeeps,
     :numAvailableMechanics,
     :maintenanceQLength,
     :breakdownQLength
 
   # model parameters
-  attr_reader  :maxJeeps,
+  attr_reader :maxJeeps,
     :maxMaintainers,
     :breakdownRate,
     :maintenanceCycleInDays,
diff --git a/demos/MMk.rb b/demos/MMk.rb
index 67bc0b4d226a4e837c061ce89b5d97a2bef11611..ccbb71223dc94ac8fda179eb14caa0f6e73ed2fc 100644
--- a/demos/MMk.rb
+++ b/demos/MMk.rb
@@ -1,10 +1,10 @@
 #!/usr/bin/env ruby
 
-require 'rubygems'
+require 'rubygems' if RUBY_VERSION =~ /^1\.8/
 require 'simplekit'
 
 # Demonstration model of an M/M/k queueing system.  There are k servers
-# and both the arrival and service processes are memoryless (exponential). 
+# and both the arrival and service processes are memoryless (exponential).
 class MMk
   include SimpleKit
 
@@ -76,4 +76,3 @@ end
 
 # Instantiate an MMk object with a particular parameterization and run it.
 MMk.new(4.5, 1.0, 5).run
-
diff --git a/demos/MyModel.rb b/demos/MyModel.rb
index 0f6e7c89845e48e8076f7f447a89530fe9da903e..b91fbee2daaf8bb890b6df03febdd2f0d65a5bbf 100644
--- a/demos/MyModel.rb
+++ b/demos/MyModel.rb
@@ -1,6 +1,6 @@
 #!/usr/bin/env ruby
 
-require 'rubygems'
+require 'rubygems' if RUBY_VERSION =~ /^1\.8/
 require 'simplekit'
 
 class MyModel
@@ -17,7 +17,6 @@ class MyModel
     schedule(:increment, 1.5)
     printf "%f, %f\n", model_time, @x
   end
-
 end
 
 MyModel.new.run
diff --git a/demos/MyModelArgs.rb b/demos/MyModelArgs.rb
index 96c9cab93262311db0480813a035e4c93cc36ad0..170bfd526a7e77195714d5dd8783b56d5c98a0e7 100644
--- a/demos/MyModelArgs.rb
+++ b/demos/MyModelArgs.rb
@@ -1,6 +1,6 @@
 #!/usr/bin/env ruby
 
-require 'rubygems'
+require 'rubygems' if RUBY_VERSION =~ /^1\.8/
 require 'simplekit'
 
 class MyModel
@@ -17,7 +17,6 @@ class MyModel
     printf "%f, %f, %c\n", model_time, @x, c
     schedule(:halt, 0.0) if model_time > 10
   end
-
 end
 
 MyModel.new.run
diff --git a/simplekit.gemspec b/simplekit.gemspec
index 4e713abea3da7e02e8457035a2a391243662d05f..e79dad90eed9dd680996e344b06f947b552e83d6 100644
--- a/simplekit.gemspec
+++ b/simplekit.gemspec
@@ -1,10 +1,10 @@
 # -*- ruby -*-
-_VERSION = "0.4.2"
+_VERSION = "0.4.3"
 
 Gem::Specification.new do |s|
   s.name = "simplekit"
   s.version = _VERSION
-  s.date = "2013-04-11"
+  s.date = "2015-05-04"
   s.summary = "Discrete event simulation engine."
   s.homepage = "git://or.nps.edu/simplekit-ruby.git"
   s.email = "pjs@alum.mit.edu"