diff --git a/.rubocop_todo/layout/line_length.yml b/.rubocop_todo/layout/line_length.yml
index ade96f48f8a..1b807c0c1f6 100644
--- a/.rubocop_todo/layout/line_length.yml
+++ b/.rubocop_todo/layout/line_length.yml
@@ -1948,7 +1948,6 @@ Layout/LineLength:
     - 'ee/spec/features/groups/security/compliance_dashboards_spec.rb'
     - 'ee/spec/features/groups/sso_spec.rb'
     - 'ee/spec/features/groups/usage_quotas_spec.rb'
-    - 'ee/spec/features/incidents/incident_details_spec.rb'
     - 'ee/spec/features/integrations/jira/jira_issues_list_spec.rb'
     - 'ee/spec/features/invites_spec.rb'
     - 'ee/spec/features/issues/filtered_search/filter_issues_weight_spec.rb'
@@ -2790,8 +2789,6 @@ Layout/LineLength:
     - 'ee/spec/services/ee/groups/autocomplete_service_spec.rb'
     - 'ee/spec/services/ee/groups/deploy_tokens/create_service_spec.rb'
     - 'ee/spec/services/ee/groups/import_export/export_service_spec.rb'
-    - 'ee/spec/services/ee/incident_management/issuable_escalation_statuses/after_update_service_spec.rb'
-    - 'ee/spec/services/ee/incident_management/issuable_escalation_statuses/prepare_update_service_spec.rb'
     - 'ee/spec/services/ee/ip_restrictions/update_service_spec.rb'
     - 'ee/spec/services/ee/issuable/common_system_notes_service_spec.rb'
     - 'ee/spec/services/ee/issuable/destroy_service_spec.rb'
diff --git a/.rubocop_todo/rspec/context_wording.yml b/.rubocop_todo/rspec/context_wording.yml
index a75e247c1ef..7becad56886 100644
--- a/.rubocop_todo/rspec/context_wording.yml
+++ b/.rubocop_todo/rspec/context_wording.yml
@@ -154,7 +154,6 @@ RSpec/ContextWording:
     - 'ee/spec/features/groups/wiki/user_views_wiki_empty_spec.rb'
     - 'ee/spec/features/groups_spec.rb'
     - 'ee/spec/features/ide/user_opens_ide_spec.rb'
-    - 'ee/spec/features/incidents/incident_details_spec.rb'
     - 'ee/spec/features/integrations/jira/jira_issues_list_spec.rb'
     - 'ee/spec/features/issues/epic_in_issue_sidebar_spec.rb'
     - 'ee/spec/features/issues/filtered_search/filter_issues_by_iteration_spec.rb'
@@ -869,7 +868,6 @@ RSpec/ContextWording:
     - 'ee/spec/services/ee/ci/job_artifacts/destroy_batch_service_spec.rb'
     - 'ee/spec/services/ee/git/branch_push_service_spec.rb'
     - 'ee/spec/services/ee/groups/autocomplete_service_spec.rb'
-    - 'ee/spec/services/ee/incident_management/issuable_escalation_statuses/after_update_service_spec.rb'
     - 'ee/spec/services/ee/integrations/test/project_service_spec.rb'
     - 'ee/spec/services/ee/ip_restrictions/update_service_spec.rb'
     - 'ee/spec/services/ee/issuable/bulk_update_service_spec.rb'
diff --git a/app/models/work_items/parent_link.rb b/app/models/work_items/parent_link.rb
index 3c405dbce3b..fc907f323e4 100644
--- a/app/models/work_items/parent_link.rb
+++ b/app/models/work_items/parent_link.rb
@@ -5,6 +5,7 @@ module WorkItems
     self.table_name = 'work_item_parent_links'
 
     MAX_CHILDREN = 100
+    PARENT_TYPES = [:issue, :incident].freeze
 
     belongs_to :work_item
     belongs_to :work_item_parent, class_name: 'WorkItem'
@@ -21,15 +22,20 @@ module WorkItems
       return unless work_item
 
       unless work_item.task?
-        errors.add :work_item, _('Only Task can be assigned as a child in hierarchy.')
+        errors.add :work_item, _('only Task can be assigned as a child in hierarchy.')
       end
     end
 
     def validate_parent_type
       return unless work_item_parent
 
-      unless work_item_parent.issue?
-        errors.add :work_item_parent, _('Only Issue can be parent of Task.')
+      base_type = work_item_parent.work_item_type.base_type.to_sym
+      unless PARENT_TYPES.include?(base_type)
+        parent_names = WorkItems::Type::BASE_TYPES.slice(*WorkItems::ParentLink::PARENT_TYPES)
+          .values.map { |type| type[:name] }
+
+        errors.add :work_item_parent, _('only %{parent_types} can be parent of Task.') %
+                                        { parent_types: parent_names.to_sentence }
       end
     end
 
@@ -37,7 +43,7 @@ module WorkItems
       return if work_item.nil? || work_item_parent.nil?
 
       if work_item.resource_parent != work_item_parent.resource_parent
-        errors.add :work_item_parent, _('Parent must be in the same project as child.')
+        errors.add :work_item_parent, _('parent must be in the same project as child.')
       end
     end
 
@@ -46,7 +52,7 @@ module WorkItems
 
       max = persisted? ? MAX_CHILDREN : MAX_CHILDREN - 1
       if work_item_parent.child_links.count > max
-        errors.add :work_item_parent, _('Parent already has maximum number of children.')
+        errors.add :work_item_parent, _('parent already has maximum number of children.')
       end
     end
   end
diff --git a/app/models/work_items/type.rb b/app/models/work_items/type.rb
index c52565196a1..e38d0ae153a 100644
--- a/app/models/work_items/type.rb
+++ b/app/models/work_items/type.rb
@@ -22,7 +22,7 @@ module WorkItems
 
     WIDGETS_FOR_TYPE = {
       issue: [Widgets::Assignees, Widgets::Description, Widgets::Hierarchy, Widgets::Weight],
-      incident: [Widgets::Description],
+      incident: [Widgets::Description, Widgets::Hierarchy],
       test_case: [Widgets::Description],
       requirement: [Widgets::Description],
       task: [Widgets::Assignees, Widgets::Description, Widgets::Hierarchy, Widgets::Weight]
diff --git a/app/models/work_items/widgets/hierarchy.rb b/app/models/work_items/widgets/hierarchy.rb
index dadd341de83..e4367bc8ff1 100644
--- a/app/models/work_items/widgets/hierarchy.rb
+++ b/app/models/work_items/widgets/hierarchy.rb
@@ -4,13 +4,13 @@ module WorkItems
   module Widgets
     class Hierarchy < Base
       def parent
-        return unless Feature.enabled?(:work_items_hierarchy, work_item.project)
+        return unless Feature.enabled?(:work_items, work_item.project)
 
         work_item.work_item_parent
       end
 
       def children
-        return WorkItem.none unless Feature.enabled?(:work_items_hierarchy, work_item.project)
+        return WorkItem.none unless Feature.enabled?(:work_items, work_item.project)
 
         work_item.work_item_children
       end
diff --git a/config/feature_flags/development/issue_email_participants.yml b/config/feature_flags/development/issue_email_participants.yml
index 1459d2bc7f5..b5ebb9d8c13 100644
--- a/config/feature_flags/development/issue_email_participants.yml
+++ b/config/feature_flags/development/issue_email_participants.yml
@@ -1,7 +1,7 @@
 ---
 name: issue_email_participants
 introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/49264
-rollout_issue_url: 
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/350460
 milestone: '13.8'
 type: development
 group: group::product planning
diff --git a/config/feature_flags/development/skip_scheduling_mirrors_for_free.yml b/config/feature_flags/development/skip_scheduling_mirrors_for_free.yml
new file mode 100644
index 00000000000..09f41fa9ff4
--- /dev/null
+++ b/config/feature_flags/development/skip_scheduling_mirrors_for_free.yml
@@ -0,0 +1,8 @@
+---
+name: skip_scheduling_mirrors_for_free
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/92377
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/367712
+milestone: '15.2'
+type: development
+group: group::source code
+default_enabled: false
diff --git a/config/metrics/aggregates/common.yml b/config/metrics/aggregates/common.yml
index 6396187a26a..a6585ddec23 100644
--- a/config/metrics/aggregates/common.yml
+++ b/config/metrics/aggregates/common.yml
@@ -59,6 +59,7 @@
   events:
     - users_creating_work_items
     - users_updating_work_item_title
+    - users_updating_weight_estimate
   feature_flag: track_work_items_activity
 - name: xmau_project_management
   operator: OR
@@ -67,6 +68,7 @@
   events:
     - users_creating_work_items
     - users_updating_work_item_title
+    - users_updating_weight_estimate
   feature_flag: track_work_items_activity
 - name: users_work_items
   operator: OR
@@ -75,4 +77,5 @@
   events:
     - users_creating_work_items
     - users_updating_work_item_title
+    - users_updating_weight_estimate
   feature_flag: track_work_items_activity
diff --git a/doc/administration/audit_event_streaming.md b/doc/administration/audit_event_streaming.md
index 8a0bf0e1695..b0884395556 100644
--- a/doc/administration/audit_event_streaming.md
+++ b/doc/administration/audit_event_streaming.md
@@ -9,6 +9,7 @@ info: To determine the technical writer assigned to the Stage/Group associated w
 > - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/332747) in GitLab 14.5 [with a flag](../administration/feature_flags.md) named `ff_external_audit_events_namespace`. Disabled by default.
 > - [Enabled on GitLab.com and by default on self-managed](https://gitlab.com/gitlab-org/gitlab/-/issues/338939) in GitLab 14.7.
 > - [Feature flag `ff_external_audit_events_namespace`](https://gitlab.com/gitlab-org/gitlab/-/issues/349588) removed in GitLab 14.8.
+> - [Subgroup events recording](https://gitlab.com/gitlab-org/gitlab/-/issues/366878) fixed in GitLab 15.2.
 
 Users can set an HTTP endpoint for a top-level group to receive all audit events about the group, its subgroups, and
 projects as structured JSON.
diff --git a/doc/ci/pipelines/index.md b/doc/ci/pipelines/index.md
index a816e452844..08264170d52 100644
--- a/doc/ci/pipelines/index.md
+++ b/doc/ci/pipelines/index.md
@@ -40,7 +40,7 @@ A typical pipeline might consist of four stages, executed in the following order
 NOTE:
 If you have a [mirrored repository that GitLab pulls from](../../user/project/repository/mirror/pull.md),
 you may need to enable pipeline triggering in your project's
-**Settings > Repository > Pull from a remote repository > Trigger pipelines for mirror updates**.
+**Settings > Repository > Mirroring repositories > Trigger pipelines for mirror updates**.
 
 ## Types of pipelines
 
diff --git a/doc/operations/incident_management/paging.md b/doc/operations/incident_management/paging.md
index ef5f6c81383..3eeeb67bf51 100644
--- a/doc/operations/incident_management/paging.md
+++ b/doc/operations/incident_management/paging.md
@@ -61,4 +61,6 @@ the rule fires. You can respond to a page or stop incident escalations by
 [updating the incident's status](incidents.md#change-incident-status) or, if applicable,
 [unsetting the incident's escalation policy](incidents.md#change-escalation-policy).
 
-To avoid duplicate pages, [incidents created from alerts](alerts.md#create-an-incident-from-an-alert) do not support independent escalation.
+In GitLab 15.1 and earlier, [incidents created from alerts](alerts.md#create-an-incident-from-an-alert)
+do not support independent escalation. In [GitLab 15.2 and later](https://gitlab.com/gitlab-org/gitlab/-/issues/356057),
+all incidents can be escalated independently.
diff --git a/doc/user/application_security/policies/scan-result-policies.md b/doc/user/application_security/policies/scan-result-policies.md
index d6f9465327b..3eee4957e2f 100644
--- a/doc/user/application_security/policies/scan-result-policies.md
+++ b/doc/user/application_security/policies/scan-result-policies.md
@@ -69,7 +69,7 @@ This rule enforces the defined actions based on the information provided.
 | Field      | Type | Possible values | Description |
 |------------|------|-----------------|-------------|
 | `type`     | `string` | `scan_finding` | The rule's type. |
-| `branches` | `array` of `string` | `[]` or the branch's name | Protected branches for this rule to consider. |
+| `branches` | `array` of `string` | `[]` or the branch's name | Applicable only to protected target branches. An empty array, `[]`, applies the rule to all protected target branches. |
 | `scanners`  | `array` of `string` | `sast`, `secret_detection`, `dependency_scanning`, `container_scanning`, `dast`, `coverage_fuzzing`, `api_fuzzing` | The security scanners for this rule to consider. |
 | `vulnerabilities_allowed`  | `integer` | Greater than or equal to zero | Number of vulnerabilities allowed before this rule is considered. |
 | `severity_levels`  | `array` of `string` | `info`, `unknown`, `low`, `medium`, `high`, `critical`| The severity levels for this rule to consider. |
diff --git a/doc/user/packages/generic_packages/index.md b/doc/user/packages/generic_packages/index.md
index 22b792e443f..8d5fc73ad4e 100644
--- a/doc/user/packages/generic_packages/index.md
+++ b/doc/user/packages/generic_packages/index.md
@@ -209,3 +209,25 @@ upload:
 The [Write CI-CD Variables in Pipeline](https://gitlab.com/guided-explorations/cfg-data/write-ci-cd-variables-in-pipeline) project contains a working example you can use to create, upload, and download generic packages in GitLab CI/CD.
 
 It also demonstrates how to manage a semantic version for the generic package: storing it in a CI/CD variable, retrieving it, incrementing it, and writing it back to the CI/CD variable when tests for the download work correctly.
+
+## Troubleshooting
+
+### Internal Server error on large file uploads to S3
+
+S3-compatible object storage [limits the size of a single PUT request to 5GB](https://docs.aws.amazon.com/AmazonS3/latest/userguide/upload-objects.html). If the `aws_signature_version` is set to `2` in the [object storage connection settings](../../../administration/object_storage.md), attempting to publish a package file larger than the 5GB limit can result in a `HTTP 500: Internal Server Error` response. 
+
+If you are receiving `HTTP 500: Internal Server Error` responses when publishing large files to S3, set the `aws_signature_version` to `4`:
+
+```ruby
+# Consolidated Object Storage settings
+gitlab_rails['object_store']['connection'] = {
+  # Other connection settings
+  `aws_signature_version` => '4'
+}
+# OR 
+# Storage-specific form settings
+gitlab_rails['packages_object_store_connection'] = {
+  # Other connection settings
+  `aws_signature_version` => '4'
+}
+```
diff --git a/lib/gitlab/usage_data_counters/known_events/work_items.yml b/lib/gitlab/usage_data_counters/known_events/work_items.yml
index 0c9c6026c46..5930e711aa2 100644
--- a/lib/gitlab/usage_data_counters/known_events/work_items.yml
+++ b/lib/gitlab/usage_data_counters/known_events/work_items.yml
@@ -9,3 +9,8 @@
   redis_slot: users
   aggregation: weekly
   feature_flag: track_work_items_activity
+- name: users_updating_weight_estimate
+  category: work_items
+  redis_slot: users
+  aggregation: weekly
+  feature_flag: track_work_items_activity
diff --git a/lib/gitlab/usage_data_counters/work_item_activity_unique_counter.rb b/lib/gitlab/usage_data_counters/work_item_activity_unique_counter.rb
index 6f5300405c7..51bca8b51fe 100644
--- a/lib/gitlab/usage_data_counters/work_item_activity_unique_counter.rb
+++ b/lib/gitlab/usage_data_counters/work_item_activity_unique_counter.rb
@@ -26,3 +26,7 @@ module Gitlab
     end
   end
 end
+
+# rubocop:disable Layout/LineLength
+Gitlab::UsageDataCounters::WorkItemActivityUniqueCounter.prepend_mod_with('Gitlab::UsageDataCounters::WorkItemActivityUniqueCounter')
+# rubocop:enable Layout/LineLength
diff --git a/locale/gitlab.pot b/locale/gitlab.pot
index a5917b76753..35b7cd01383 100644
--- a/locale/gitlab.pot
+++ b/locale/gitlab.pot
@@ -27101,18 +27101,12 @@ msgstr ""
 msgid "Only Issue ID or merge request ID is required"
 msgstr ""
 
-msgid "Only Issue can be parent of Task."
-msgstr ""
-
 msgid "Only Project Members"
 msgstr ""
 
 msgid "Only SSH"
 msgstr ""
 
-msgid "Only Task can be assigned as a child in hierarchy."
-msgstr ""
-
 msgid "Only accessible by %{membersPageLinkStart}project members%{membersPageLinkEnd}. Membership must be explicitly granted to each user."
 msgstr ""
 
@@ -27880,18 +27874,12 @@ msgstr ""
 msgid "Parent"
 msgstr ""
 
-msgid "Parent already has maximum number of children."
-msgstr ""
-
 msgid "Parent epic doesn't exist."
 msgstr ""
 
 msgid "Parent epic is not present."
 msgstr ""
 
-msgid "Parent must be in the same project as child."
-msgstr ""
-
 msgid "Parsing error for param :embed_json. %{message}"
 msgstr ""
 
@@ -46531,6 +46519,12 @@ msgstr ""
 msgid "on track"
 msgstr ""
 
+msgid "only %{parent_types} can be parent of Task."
+msgstr ""
+
+msgid "only Task can be assigned as a child in hierarchy."
+msgstr ""
+
 msgid "only available on top-level groups."
 msgstr ""
 
@@ -46562,6 +46556,12 @@ msgid_plural "parents"
 msgstr[0] ""
 msgstr[1] ""
 
+msgid "parent already has maximum number of children."
+msgstr ""
+
+msgid "parent must be in the same project as child."
+msgstr ""
+
 msgid "password"
 msgstr ""
 
diff --git a/package.json b/package.json
index 25aa1f8a604..af8f6ca3b8d 100644
--- a/package.json
+++ b/package.json
@@ -113,7 +113,7 @@
     "dateformat": "^5.0.1",
     "deckar01-task_list": "^2.3.1",
     "diff": "^3.4.0",
-    "dompurify": "^2.3.8",
+    "dompurify": "^2.3.9",
     "dropzone": "^4.2.0",
     "editorconfig": "^0.15.3",
     "emoji-regex": "^10.0.0",
diff --git a/spec/factories/work_items.rb b/spec/factories/work_items.rb
index e80aa9cc008..81c9fb6ed87 100644
--- a/spec/factories/work_items.rb
+++ b/spec/factories/work_items.rb
@@ -14,5 +14,10 @@ FactoryBot.define do
       issue_type { :task }
       association :work_item_type, :default, :task
     end
+
+    trait :incident do
+      issue_type { :incident }
+      association :work_item_type, :default, :incident
+    end
   end
 end
diff --git a/spec/lib/gitlab/usage_data_counters/work_item_activity_unique_counter_spec.rb b/spec/lib/gitlab/usage_data_counters/work_item_activity_unique_counter_spec.rb
index 4561d898479..0264236f087 100644
--- a/spec/lib/gitlab/usage_data_counters/work_item_activity_unique_counter_spec.rb
+++ b/spec/lib/gitlab/usage_data_counters/work_item_activity_unique_counter_spec.rb
@@ -5,46 +5,6 @@ require 'spec_helper'
 RSpec.describe Gitlab::UsageDataCounters::WorkItemActivityUniqueCounter, :clean_gitlab_redis_shared_state do
   let(:user) { build(:user, id: 1) }
 
-  shared_examples 'counter that does not track the event' do
-    it 'does not track the event' do
-      expect { 3.times { track_event } }.to not_change {
-        Gitlab::UsageDataCounters::HLLRedisCounter.unique_events(
-          event_names: event_name,
-          start_date: 2.weeks.ago,
-          end_date: 2.weeks.from_now
-        )
-      }
-    end
-  end
-
-  shared_examples 'work item unique counter' do
-    context 'when track_work_items_activity FF is enabled' do
-      it 'tracks a unique event only once' do
-        expect { 3.times { track_event } }.to change {
-          Gitlab::UsageDataCounters::HLLRedisCounter.unique_events(
-            event_names: event_name,
-            start_date: 2.weeks.ago,
-            end_date: 2.weeks.from_now
-          )
-        }.by(1)
-      end
-
-      context 'when author is nil' do
-        let(:user) { nil }
-
-        it_behaves_like 'counter that does not track the event'
-      end
-    end
-
-    context 'when track_work_items_activity FF is disabled' do
-      before do
-        stub_feature_flags(track_work_items_activity: false)
-      end
-
-      it_behaves_like 'counter that does not track the event'
-    end
-  end
-
   describe '.track_work_item_created_action' do
     subject(:track_event) { described_class.track_work_item_created_action(author: user) }
 
diff --git a/spec/models/work_items/parent_link_spec.rb b/spec/models/work_items/parent_link_spec.rb
index 9516baa7340..8abdb4e10b8 100644
--- a/spec/models/work_items/parent_link_spec.rb
+++ b/spec/models/work_items/parent_link_spec.rb
@@ -15,32 +15,37 @@ RSpec.describe WorkItems::ParentLink do
     describe 'hierarchy' do
       let_it_be(:project) { create(:project) }
       let_it_be(:issue) { build(:work_item, project: project) }
+      let_it_be(:incident) { build(:work_item, :incident, project: project) }
       let_it_be(:task1) { build(:work_item, :task, project: project) }
       let_it_be(:task2) { build(:work_item, :task, project: project) }
 
-      it 'is valid if not-task parent has task child' do
+      it 'is valid if issue parent has task child' do
         expect(build(:parent_link, work_item: task1, work_item_parent: issue)).to be_valid
       end
 
+      it 'is valid if incident parent has task child' do
+        expect(build(:parent_link, work_item: task1, work_item_parent: incident)).to be_valid
+      end
+
       it 'is not valid if child is not task' do
         link = build(:parent_link, work_item: issue)
 
         expect(link).not_to be_valid
-        expect(link.errors[:work_item]).to include('Only Task can be assigned as a child in hierarchy.')
+        expect(link.errors[:work_item]).to include('only Task can be assigned as a child in hierarchy.')
       end
 
       it 'is not valid if parent is task' do
         link = build(:parent_link, work_item_parent: task1)
 
         expect(link).not_to be_valid
-        expect(link.errors[:work_item_parent]).to include('Only Issue can be parent of Task.')
+        expect(link.errors[:work_item_parent]).to include('only Issue and Incident can be parent of Task.')
       end
 
       it 'is not valid if parent is in other project' do
         link = build(:parent_link, work_item_parent: task1, work_item: build(:work_item))
 
         expect(link).not_to be_valid
-        expect(link.errors[:work_item_parent]).to include('Parent must be in the same project as child.')
+        expect(link.errors[:work_item_parent]).to include('parent must be in the same project as child.')
       end
 
       context 'when parent already has maximum number of links' do
@@ -54,7 +59,7 @@ RSpec.describe WorkItems::ParentLink do
           link2 = build(:parent_link, work_item_parent: issue, work_item: task2)
 
           expect(link2).not_to be_valid
-          expect(link2.errors[:work_item_parent]).to include('Parent already has maximum number of children.')
+          expect(link2.errors[:work_item_parent]).to include('parent already has maximum number of children.')
         end
 
         it 'existing link is still valid' do
diff --git a/spec/models/work_items/widgets/hierarchy_spec.rb b/spec/models/work_items/widgets/hierarchy_spec.rb
index 0141731529b..6d05953ecff 100644
--- a/spec/models/work_items/widgets/hierarchy_spec.rb
+++ b/spec/models/work_items/widgets/hierarchy_spec.rb
@@ -24,9 +24,9 @@ RSpec.describe WorkItems::Widgets::Hierarchy do
 
     it { is_expected.to eq parent_link.work_item_parent }
 
-    context 'when work_items_hierarchy flag is disabled' do
+    context 'when work_items flag is disabled' do
       before do
-        stub_feature_flags(work_items_hierarchy: false)
+        stub_feature_flags(work_items: false)
       end
 
       it { is_expected.to be_nil }
@@ -41,9 +41,9 @@ RSpec.describe WorkItems::Widgets::Hierarchy do
 
     it { is_expected.to match_array([parent_link1.work_item, parent_link2.work_item]) }
 
-    context 'when work_items_hierarchy flag is disabled' do
+    context 'when work_items flag is disabled' do
       before do
-        stub_feature_flags(work_items_hierarchy: false)
+        stub_feature_flags(work_items: false)
       end
 
       it { is_expected.to be_empty }
diff --git a/spec/requests/api/graphql/mutations/work_items/create_spec.rb b/spec/requests/api/graphql/mutations/work_items/create_spec.rb
index c33dda67a25..3496ab38ee8 100644
--- a/spec/requests/api/graphql/mutations/work_items/create_spec.rb
+++ b/spec/requests/api/graphql/mutations/work_items/create_spec.rb
@@ -120,7 +120,8 @@ RSpec.describe 'Create a work item' do
           it 'returns error' do
             post_graphql_mutation(mutation, current_user: current_user)
 
-            expect(mutation_response['errors']).to contain_exactly(/cannot be added: Only Issue can be parent of Task./)
+            expect(mutation_response['errors'])
+              .to contain_exactly(/cannot be added: only Issue and Incident can be parent of Task./)
             expect(mutation_response['workItem']).to be_nil
           end
         end
diff --git a/spec/requests/api/graphql/mutations/work_items/update_spec.rb b/spec/requests/api/graphql/mutations/work_items/update_spec.rb
index e2c4386772c..b5f0eb7fbf6 100644
--- a/spec/requests/api/graphql/mutations/work_items/update_spec.rb
+++ b/spec/requests/api/graphql/mutations/work_items/update_spec.rb
@@ -170,7 +170,7 @@ RSpec.describe 'Update a work item' do
         let_it_be(:invalid_parent) { create(:work_item, :task, project: project) }
 
         context 'when parent work item type is invalid' do
-          let(:error) { "#{work_item.to_reference} cannot be added: Only Issue can be parent of Task." }
+          let(:error) { "#{work_item.to_reference} cannot be added: only Issue and Incident can be parent of Task." }
           let(:input) do
             { 'hierarchyWidget' => { 'parentId' => invalid_parent.to_global_id.to_s }, 'title' => 'new title' }
           end
@@ -281,7 +281,7 @@ RSpec.describe 'Update a work item' do
 
         let(:input) { { 'hierarchyWidget' => { 'childrenIds' => children_ids } } }
         let(:error) do
-          "#{invalid_child.to_reference} cannot be added: Only Task can be assigned as a child in hierarchy."
+          "#{invalid_child.to_reference} cannot be added: only Task can be assigned as a child in hierarchy."
         end
 
         context 'when child work item type is invalid' do
diff --git a/spec/services/work_items/create_and_link_service_spec.rb b/spec/services/work_items/create_and_link_service_spec.rb
index 36038768d1a..81be15f9e2f 100644
--- a/spec/services/work_items/create_and_link_service_spec.rb
+++ b/spec/services/work_items/create_and_link_service_spec.rb
@@ -68,7 +68,7 @@ RSpec.describe WorkItems::CreateAndLinkService do
         end
 
         it 'returns a link creation error message' do
-          expect(service_result.errors).to contain_exactly(/Only Issue can be parent of Task./)
+          expect(service_result.errors).to contain_exactly(/only Issue and Incident can be parent of Task./)
         end
       end
     end
diff --git a/spec/services/work_items/create_service_spec.rb b/spec/services/work_items/create_service_spec.rb
index 0d3c5391a4f..7b44601bfdd 100644
--- a/spec/services/work_items/create_service_spec.rb
+++ b/spec/services/work_items/create_service_spec.rb
@@ -148,7 +148,7 @@ RSpec.describe WorkItems::CreateService do
             expect { service_result }.not_to change(WorkItem, :count)
 
             expect(service_result[:status]).to be(:error)
-            expect(service_result[:message]).to match(/Only Issue can be parent of Task./)
+            expect(service_result[:message]).to match(/only Issue and Incident can be parent of Task./)
           end
         end
 
diff --git a/spec/services/work_items/parent_links/create_service_spec.rb b/spec/services/work_items/parent_links/create_service_spec.rb
index 3e3d65a8615..7aa90d01a0b 100644
--- a/spec/services/work_items/parent_links/create_service_spec.rb
+++ b/spec/services/work_items/parent_links/create_service_spec.rb
@@ -102,8 +102,8 @@ RSpec.describe WorkItems::ParentLinks::CreateService do
         end
 
         it 'returns error status' do
-          error = "#{issue.to_reference} cannot be added: Only Task can be assigned as a child in hierarchy.. " \
-            "#{other_project_task.to_reference} cannot be added: Parent must be in the same project as child."
+          error = "#{issue.to_reference} cannot be added: only Task can be assigned as a child in hierarchy.. " \
+            "#{other_project_task.to_reference} cannot be added: parent must be in the same project as child."
 
           is_expected.to eq(service_error(error, http_status: 422))
         end
@@ -115,7 +115,7 @@ RSpec.describe WorkItems::ParentLinks::CreateService do
         let(:params) { { target_issuable: task1 } }
 
         it 'returns error status' do
-          error = "#{task1.to_reference} cannot be added: Only Issue can be parent of Task."
+          error = "#{task1.to_reference} cannot be added: only Issue and Incident can be parent of Task."
 
           is_expected.to eq(service_error(error, http_status: 422))
         end
@@ -129,7 +129,7 @@ RSpec.describe WorkItems::ParentLinks::CreateService do
         end
 
         it 'returns error status' do
-          error = "#{task2.to_reference} cannot be added: Parent already has maximum number of children."
+          error = "#{task2.to_reference} cannot be added: parent already has maximum number of children."
 
           is_expected.to eq(service_error(error, http_status: 422))
         end
diff --git a/spec/services/work_items/update_service_spec.rb b/spec/services/work_items/update_service_spec.rb
index 25b8caba0e8..3423b92e35c 100644
--- a/spec/services/work_items/update_service_spec.rb
+++ b/spec/services/work_items/update_service_spec.rb
@@ -165,7 +165,7 @@ RSpec.describe WorkItems::UpdateService do
           it 'returns error status' do
             expect(subject[:status]).to be(:error)
             expect(subject[:message])
-              .to match("#{child_work_item.to_reference} cannot be added: Only Task can be assigned as a child in hierarchy.")
+              .to match("#{child_work_item.to_reference} cannot be added: only Task can be assigned as a child in hierarchy.")
           end
 
           it 'does not update work item attributes' do
diff --git a/spec/services/work_items/widgets/hierarchy_service/update_service_spec.rb b/spec/services/work_items/widgets/hierarchy_service/update_service_spec.rb
index 528e20f95ad..c48e17431bf 100644
--- a/spec/services/work_items/widgets/hierarchy_service/update_service_spec.rb
+++ b/spec/services/work_items/widgets/hierarchy_service/update_service_spec.rb
@@ -85,7 +85,7 @@ RSpec.describe WorkItems::Widgets::HierarchyService::UpdateService do
 
           it_behaves_like 'raises a WidgetError' do
             let(:message) do
-              "#{child_issue.to_reference} cannot be added: Only Task can be assigned as a child in hierarchy."
+              "#{child_issue.to_reference} cannot be added: only Task can be assigned as a child in hierarchy."
             end
           end
         end
@@ -149,7 +149,9 @@ RSpec.describe WorkItems::Widgets::HierarchyService::UpdateService do
           let(:params) {{ parent: parent_task } }
 
           it_behaves_like 'raises a WidgetError' do
-            let(:message) { "#{work_item.to_reference} cannot be added: Only Issue can be parent of Task." }
+            let(:message) do
+              "#{work_item.to_reference} cannot be added: only Issue and Incident can be parent of Task."
+            end
           end
         end
       end
diff --git a/spec/support/shared_examples/usage_data_counters/work_item_activity_unique_counter_shared_examples.rb b/spec/support/shared_examples/usage_data_counters/work_item_activity_unique_counter_shared_examples.rb
new file mode 100644
index 00000000000..4655585a092
--- /dev/null
+++ b/spec/support/shared_examples/usage_data_counters/work_item_activity_unique_counter_shared_examples.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+RSpec.shared_examples 'counter that does not track the event' do
+  it 'does not track the event' do
+    expect { 3.times { track_event } }.to not_change {
+      Gitlab::UsageDataCounters::HLLRedisCounter.unique_events(
+        event_names: event_name,
+        start_date: 2.weeks.ago,
+        end_date: 2.weeks.from_now
+      )
+    }
+  end
+end
+
+RSpec.shared_examples 'work item unique counter' do
+  context 'when track_work_items_activity FF is enabled' do
+    it 'tracks a unique event only once' do
+      expect { 3.times { track_event } }.to change {
+        Gitlab::UsageDataCounters::HLLRedisCounter.unique_events(
+          event_names: event_name,
+          start_date: 2.weeks.ago,
+          end_date: 2.weeks.from_now
+        )
+      }.by(1)
+    end
+
+    context 'when author is nil' do
+      let(:user) { nil }
+
+      it_behaves_like 'counter that does not track the event'
+    end
+  end
+
+  context 'when track_work_items_activity FF is disabled' do
+    before do
+      stub_feature_flags(track_work_items_activity: false)
+    end
+
+    it_behaves_like 'counter that does not track the event'
+  end
+end
diff --git a/workhorse/internal/badgateway/embed/gitlab-logo-500.png b/workhorse/internal/badgateway/embed/gitlab-logo-500.png
new file mode 100644
index 00000000000..516f5bb27a1
Binary files /dev/null and b/workhorse/internal/badgateway/embed/gitlab-logo-500.png differ
diff --git a/workhorse/internal/badgateway/roundtripper.go b/workhorse/internal/badgateway/roundtripper.go
index 240a4ebc86b..cc982b092a7 100644
--- a/workhorse/internal/badgateway/roundtripper.go
+++ b/workhorse/internal/badgateway/roundtripper.go
@@ -2,6 +2,8 @@ package badgateway
 
 import (
 	"bytes"
+	_ "embed"
+	"encoding/base64"
 	"fmt"
 	"html/template"
 	"io"
@@ -12,6 +14,9 @@ import (
 	"gitlab.com/gitlab-org/gitlab/workhorse/internal/log"
 )
 
+//go:embed embed/gitlab-logo-500.png
+var gitlabLogo []byte
+
 // Error is a custom error for pretty Sentry 'issues'
 type sentryError struct{ error }
 
@@ -68,9 +73,10 @@ func (t *roundTripper) RoundTrip(r *http.Request) (*http.Response, error) {
 
 func developmentModeResponse(err error) (body string, contentType string) {
 	data := TemplateData{
-		Time:          time.Now().Format("15:04:05"),
-		Error:         err.Error(),
-		ReloadSeconds: 5,
+		Time:                    time.Now().Format("15:04:05"),
+		Error:                   err.Error(),
+		ReloadSeconds:           5,
+		Base64EncodedGitLabLogo: base64.StdEncoding.EncodeToString(gitlabLogo),
 	}
 
 	buf := &bytes.Buffer{}
@@ -82,28 +88,44 @@ func developmentModeResponse(err error) (body string, contentType string) {
 }
 
 type TemplateData struct {
-	Time          string
-	Error         string
-	ReloadSeconds int
+	Time                    string
+	Error                   string
+	ReloadSeconds           int
+	Base64EncodedGitLabLogo string
 }
 
 var developmentErrorTemplate = template.Must(template.New("error502").Parse(`
-<html>
+<!DOCTYPE html>
+<html lang="en">
+
 <head>
-<title>502: GitLab is not responding</title>
-<script>
-window.setTimeout(function() { location.reload() }, {{.ReloadSeconds}} * 1000)
-</script>
+	<title>Waiting for GitLab to boot</title>
 </head>
 
 <body>
-<h1>502</h1>
-<p>GitLab is not responding. The error was:</p>
+	<div style="text-align: center; font-family: Source Sans Pro, sans-serif">
+ 		<img style="padding: 60px 0" src="data:image/png;base64,{{.Base64EncodedGitLabLogo}}" alt="GitLab" />
 
-<pre>{{.Error}}</pre>
+		<h1>Waiting for GitLab to boot</h1>
 
-<p>If you just started GDK it can take 60-300 seconds before GitLab has finished booting. This page will automatically reload every {{.ReloadSeconds}} seconds.</p>
-<footer>Generated by gitlab-workhorse running in development mode at {{.Time}}.</footer>
+		<pre>{{.Error}}</pre>
+
+		<br/>
+
+		<p>It can take 60-180 seconds for GitLab to boot completely.</p>
+		<p>This page will automatically reload every {{.ReloadSeconds}} seconds.</p>
+
+		<br/>
+
+		<footer>
+			<p>Generated by gitlab-workhorse running in development mode at {{.Time}}.</p>
+		</footer>
+	</div>
+
+	<script>
+		window.setTimeout(function() { location.reload(); }, {{.ReloadSeconds}} * 1000)
+	</script>
 </body>
+
 </html>
 `))