diff --git a/Gemfile b/Gemfile
index da5807c3eb4..072a26200d8 100644
--- a/Gemfile
+++ b/Gemfile
@@ -295,7 +295,9 @@ gem 'roar', '~> 1.1.0'
 gem 'rack-cors', '~> 1.1.1'
 
 # Required for contracts
-gem 'disposable', '~> 0.4.7'
+# Not requiring since it needs to be patched before initialization:
+# See lib/open_project/patches/disposable.rb
+gem 'disposable', '~> 0.6.1', require: false
 
 platforms :mri, :mingw, :x64_mingw do
   group :postgres do
diff --git a/Gemfile.lock b/Gemfile.lock
index 30ca270e0d3..c2d55493f1a 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -406,12 +406,9 @@ GEM
       activerecord (>= 3.0, < 6.2)
       delayed_job (>= 3.0, < 5)
     diff-lcs (1.4.4)
-    disposable (0.4.7)
+    disposable (0.6.1)
       declarative (>= 0.0.9, < 1.0.0)
-      declarative-builder (< 0.2.0)
-      declarative-option (< 0.2.0)
-      representable (>= 2.4.0, <= 3.1.0)
-      uber (< 0.2.0)
+      representable (>= 3.1.1, < 3.2.0)
     domain_name (0.5.20190701)
       unf (>= 0.0.5, < 1.0.0)
     doorkeeper (5.5.4)
@@ -782,9 +779,9 @@ GEM
       json
     redcarpet (3.5.1)
     regexp_parser (2.1.1)
-    representable (3.1.0)
+    representable (3.1.1)
       declarative (< 0.1.0)
-      trailblazer-option (~> 0.1.0)
+      trailblazer-option (>= 0.1.1, < 0.2.0)
       uber (< 0.2.0)
     request_store (1.5.0)
       rack (>= 1.4)
@@ -1011,7 +1008,7 @@ DEPENDENCIES
   deckar01-task_list (~> 2.3.1)
   delayed_cron_job (~> 0.9.0)
   delayed_job_active_record (~> 4.1.5)
-  disposable (~> 0.4.7)
+  disposable (~> 0.6.1)
   doorkeeper (~> 5.5.0)
   email_validator (~> 2.2.3)
   equivalent-xml (~> 0.6)
diff --git a/lib/open_project/patches/disposable.rb b/lib/open_project/patches/disposable.rb
new file mode 100644
index 00000000000..5fd71bede98
--- /dev/null
+++ b/lib/open_project/patches/disposable.rb
@@ -0,0 +1,61 @@
+#-- copyright
+# OpenProject is an open source project management software.
+# Copyright (C) 2012-2021 the OpenProject GmbH
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License version 3.
+#
+# OpenProject is a fork of ChiliProject, which is a fork of Redmine. The copyright follows:
+# Copyright (C) 2006-2013 Jean-Philippe Lang
+# Copyright (C) 2010-2013 the ChiliProject Team
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+#
+# See COPYRIGHT and LICENSE files for more details.
+#++
+
+# Disposable from 0.6.0 on includes Forwardable into every
+# class inheriting from Disposable::Twin. OpenProject
+# uses Disposable::Twin for the contracts.
+# Including Forwardable overwrites the rails core_ext delegate
+# on which e.g. ActiveModel::Naming relies.
+OpenProject::Patches.patch_gem_version 'disposable', '6.0.1' do
+  # The patch thus loads the module including Forwardable, then removes the
+  # code and defines its own empty module.
+  module Disposable
+    class Twin
+      module Property
+
+      end
+    end
+  end
+
+  require "disposable/twin/property/unnest"
+  Disposable::Twin::Property.send(:remove_const, :Unnest)
+
+  module Disposable
+    class Twin
+      module Property
+        module Unnest
+          def unnest(_name, _options)
+            raise 'Relying on patched away method'
+          end
+        end
+      end
+    end
+  end
+
+  require 'disposable'
+end
diff --git a/lib/open_project/patches/representable.rb b/lib/open_project/patches/representable.rb
index c0b508da60a..468181306ae 100644
--- a/lib/open_project/patches/representable.rb
+++ b/lib/open_project/patches/representable.rb
@@ -70,7 +70,7 @@ module OpenProject::Patches::Representable
   end
 end
 
-OpenProject::Patches.patch_gem_version 'representable', '3.1.0' do
+OpenProject::Patches.patch_gem_version 'representable', '3.1.1' do
   unless Representable::Decorator.included_modules.include?(OpenProject::Patches::Representable::DecoratorPatch)
     Representable::Decorator.include OpenProject::Patches::Representable::DecoratorPatch
   end