diff --git a/lib/puppet-debugserver/debug_session/hook_handlers.rb b/lib/puppet-debugserver/debug_session/hook_handlers.rb
index 565c7a9f..56948d62 100644
--- a/lib/puppet-debugserver/debug_session/hook_handlers.rb
+++ b/lib/puppet-debugserver/debug_session/hook_handlers.rb
@@ -256,7 +256,11 @@ def process_breakpoint_hook(reason, args)
         end
 
         break_description = break_display_text if break_description.empty?
-        stack_trace = Puppet::Pops::PuppetStack.stacktrace
+        # Due to a modification to the way stack traces are treated in Puppet 6.11.0, the stack
+        # now includes entries for files in Line 0, which doesn't exist. These indicate that a file
+        # has started to be processed/parsed/compiled. So we just ignore them
+        # See https://tickets.puppetlabs.com/browse/PUP-10150 for more infomation
+        stack_trace = Puppet::Pops::PuppetStack.stacktrace.reject { |item| item[1].zero? }
         # Due to https://github.com/puppetlabs/puppet/commit/0f96dd918b6184261bc2219e5e68e246ffbeac10
         # Prior to Puppet 4.8.0, stacktrace is in reverse order
         stack_trace.reverse! if Gem::Version.new(Puppet.version) < Gem::Version.new('4.8.0')
diff --git a/lib/puppet-languageserver-sidecar/puppet_monkey_patches_puppetstrings.rb b/lib/puppet-languageserver-sidecar/puppet_monkey_patches_puppetstrings.rb
index e1a2b0ff..78290e8d 100644
--- a/lib/puppet-languageserver-sidecar/puppet_monkey_patches_puppetstrings.rb
+++ b/lib/puppet-languageserver-sidecar/puppet_monkey_patches_puppetstrings.rb
@@ -69,6 +69,84 @@ def discover_paths(type, name_authority = Pcore::RUNTIME_NAME_AUTHORITY)
   end
 end
 
+# The Null Loader was removed in Puppet 6.11.0+ (and friends) so monkey patch it back in!
+# Last known source is at - https://github.com/puppetlabs/puppet/blob/6.10.1/lib/puppet/pops/loader/null_loader.rb
+if defined?(::Puppet::Pops::Loader::NullLoader).nil?
+  # This came direct from Puppet so ignore Rubocop
+  # rubocop:disable Lint/UnusedMethodArgument
+  # rubocop:disable Style/ClassAndModuleChildren
+  # rubocop:disable Layout/SpaceAroundEqualsInParameterDefault
+  # rubocop:disable Style/StringLiterals
+  # rubocop:disable Style/TrivialAccessors
+  # rubocop:disable Style/DefWithParentheses
+  # The null loader is empty and delegates everything to its parent if it has one.
+  #
+  class ::Puppet::Pops::Loader::NullLoader < ::Puppet::Pops::Loader::Loader
+    attr_reader :loader_name
+
+    # Construct a NullLoader, optionally with a parent loader
+    #
+    def initialize(parent_loader=nil, loader_name = "null-loader")
+      super(loader_name)
+      @parent = parent_loader
+    end
+
+    # Has parent if one was set when constructed
+    def parent
+      @parent
+    end
+
+    def find(typed_name)
+      if @parent.nil?
+        nil
+      else
+        @parent.find(typed_name)
+      end
+    end
+
+    def load_typed(typed_name)
+      if @parent.nil?
+        nil
+      else
+        @parent.load_typed(typed_name)
+      end
+    end
+
+    def loaded_entry(typed_name, check_dependencies = false)
+      if @parent.nil?
+        nil
+      else
+        @parent.loaded_entry(typed_name, check_dependencies)
+      end
+    end
+
+    # Has no entries on its own - always nil
+    def get_entry(typed_name)
+      nil
+    end
+
+    # Finds nothing, there are no entries
+    def find(name)
+      nil
+    end
+
+    # Cannot store anything
+    def set_entry(typed_name, value, origin = nil)
+      nil
+    end
+
+    def to_s()
+      "(NullLoader '#{loader_name}')"
+    end
+  end
+  # rubocop:enable Lint/UnusedMethodArgument
+  # rubocop:enable Style/ClassAndModuleChildren
+  # rubocop:enable Layout/SpaceAroundEqualsInParameterDefault
+  # rubocop:enable Style/StringLiterals
+  # rubocop:enable Style/TrivialAccessors
+  # rubocop:enable Style/DefWithParentheses
+end
+
 # While this is not a monkey patch, but a new class, this class is used purely to
 # enumerate the paths of puppet "things" that aren't already covered as part of the
 # usual loaders. It is implemented as a null loader as it can't actually _load_
diff --git a/spec/debugserver/integration/puppet-debugserver/end_to_end_spec.rb b/spec/debugserver/integration/puppet-debugserver/end_to_end_spec.rb
index 9a7f9dd7..bbf29f3c 100644
--- a/spec/debugserver/integration/puppet-debugserver/end_to_end_spec.rb
+++ b/spec/debugserver/integration/puppet-debugserver/end_to_end_spec.rb
@@ -32,6 +32,12 @@
     @debug_stderr.close
   }
 
+  def modified_puppet_stack_trace
+    # Due to a modification to the way stack traces are treated in Puppet 6.11.0, the stack size is different
+    # See https://tickets.puppetlabs.com/browse/PUP-10150 for more infomation
+    @modified_puppet_stack_trace ||= Gem::Version.create(Puppet.version) >= Gem::Version.create('6.11.0')
+  end
+
   context 'Processing an empty manifest with no breakpoints' do
     let(:manifest_file) { File.join($fixtures_dir, 'environments', 'testfixtures', 'manifests', 'empty.pp') }
     let(:noop) { true }
@@ -92,10 +98,14 @@
       result = @client.data_from_request_seq_id(@client.current_seq_id)
       # As we're only in the root, only two frames should be available.  The error and where it was called from
       expect(result['success']).to be true
-      expect(result['body']['stackFrames'].count).to eq(2)
-      expect(result['body']['stackFrames'][0]).to include('line' => 3)
-      expect(result['body']['stackFrames'][1]).to include('line' => 3)
-
+      if modified_puppet_stack_trace
+        expect(result['body']['stackFrames'].count).to eq(1)
+        expect(result['body']['stackFrames'][0]).to include('line' => 3)
+      else
+        expect(result['body']['stackFrames'].count).to eq(2)
+        expect(result['body']['stackFrames'][0]).to include('line' => 3)
+        expect(result['body']['stackFrames'][1]).to include('line' => 3)
+      end
       # continue_request
       @client.send_data(@client.continue_request(@client.next_seq_id, thread_id))
       expect(@client).to receive_message_with_request_id_within_timeout([@client.current_seq_id, 5])