diff --git a/Gemfile b/Gemfile
index ba9393b..8a1b9fe 100644
--- a/Gemfile
+++ b/Gemfile
@@ -6,16 +6,4 @@ gemspec
 # Used for local development/testing only
 gem 'rake'
 
-if RUBY_VERSION =~ /^1\./
-  gem 'tins', '< 1.7' # The 'tins' gem requires Ruby 2.x on/after this version
-  gem 'json', '< 2.0' # The 'json' gem drops pre-Ruby 2.x support on/after this version
-  gem 'term-ansicolor', '< 1.4' # The 'term-ansicolor' gem requires Ruby 2.x on/after this version
-
-  # ffi gem for Windows requires Ruby 2.x on/after this version
-  gem 'ffi', '< 1.9.15' if ENV['CHILDPROCESS_POSIX_SPAWN'] == 'true' || Gem.win_platform?
-elsif Gem::Version.new(RUBY_VERSION) < Gem::Version.new('2.2')
-  # Ruby 2.0/2.1 support only ffi before 1.10
-  gem 'ffi', '~> 1.9.0' if ENV['CHILDPROCESS_POSIX_SPAWN'] == 'true' || Gem.win_platform?
-else
-  gem 'ffi' if ENV['CHILDPROCESS_POSIX_SPAWN'] == 'true' || Gem.win_platform?
-end
+gem 'ffi' if ENV['CHILDPROCESS_POSIX_SPAWN'] == 'true' || Gem.win_platform?
diff --git a/lib/childprocess/unix/platform/arm64-macosx.rb b/lib/childprocess/unix/platform/arm64-macosx.rb
new file mode 100644
index 0000000..fc0383d
--- /dev/null
+++ b/lib/childprocess/unix/platform/arm64-macosx.rb
@@ -0,0 +1,11 @@
+module ChildProcess::Unix::Platform
+  SIZEOF = {
+     :posix_spawn_file_actions_t => 8,
+     :posix_spawnattr_t          => 8,
+     :sigset_t                   => 4
+  }
+  POSIX_SPAWN_RESETIDS   = 1
+  POSIX_SPAWN_SETPGROUP  = 2
+  POSIX_SPAWN_SETSIGDEF  = 4
+  POSIX_SPAWN_SETSIGMASK = 8
+end
diff --git a/spec/childprocess_spec.rb b/spec/childprocess_spec.rb
index 89bb235..ffd7240 100644
--- a/spec/childprocess_spec.rb
+++ b/spec/childprocess_spec.rb
@@ -195,7 +195,7 @@
 
     Tempfile.open('grandparent_out') do |gp_file|
       # Create a parent and detached child process that will spit out their PID. Make sure that the child process lasts longer than the parent.
-      p_process = ruby("require 'childprocess' ; c_process = ChildProcess.build('ruby', '-e', 'puts \\\"Child PID: \#{Process.pid}\\\" ; sleep 5') ; c_process.io.inherit! ; c_process.detach = true ;  c_process.start ; puts \"Child PID: \#{c_process.pid}\" ; puts \"Parent PID: \#{Process.pid}\"")
+      p_process = ruby("$: << 'lib'; require 'childprocess' ; c_process = ChildProcess.build('ruby', '-e', 'puts \\\"Child PID: \#{Process.pid}\\\" ; sleep 5') ; c_process.io.inherit! ; c_process.detach = true ;  c_process.start ; puts \"Child PID: \#{c_process.pid}\" ; puts \"Parent PID: \#{Process.pid}\"")
       p_process.io.stdout = p_process.io.stderr = gp_file
 
       # Let the parent process die
diff --git a/spec/io_spec.rb b/spec/io_spec.rb
index 17bd526..cd3777d 100644
--- a/spec/io_spec.rb
+++ b/spec/io_spec.rb
@@ -138,7 +138,7 @@
 
       stdin.close
       process.poll_for_exit(exit_timeout)
-     ensure
+    ensure
       out_receiver.close
       out.close
     end