Replace old handbook URLs

Author: axilleas

doc/development/adding-deprecation-messages.md

@@ -6,7 +6,7 @@ info: To determine the technical writer assigned to the Stage/Group associated w
 
 # Omnibus GitLab deprecation process
 
-Besides following the [GitLab deprecation guidelines](https://about.gitlab.com/handbook/product/gitlab-the-product/#deprecations-removals-and-breaking-changes), we should also add deprecation messages
+Besides following the [GitLab deprecation guidelines](https://handbook.gitlab.com/handbook/product/gitlab-the-product/#deprecations-removals-and-breaking-changes), we should also add deprecation messages
 to the Omnibus GitLab package.
 
 Notifying GitLab administrators of the deprecation and removal of features through deprecation messages consists of:

doc/development/broken_master.md

@@ -10,14 +10,14 @@ We currently run [nightly pipelines](pipelines.md#scheduled-pipelines) for
 building both CE and EE package in [our Release mirror](https://dev.gitlab.org/gitlab/omnibus-gitlab).
 This mirror is configured to send pipeline failure notifications to
 `#g_distribution` channel on Slack. A broken master pipeline gets priority over
-other scheduled work as per our [development guidelines](https://about.gitlab.com/handbook/engineering/workflow/#resolution-of-broken-master).
+other scheduled work as per our [development guidelines](https://handbook.gitlab.com/handbook/engineering/workflow/#resolution-of-broken-master).
 
 ## Jobs are stuck due to no runners being active
 
 This is a transient error due to connection issues between runner manager
 machine and `dev.gitlab.org`.
 
-1. Sign in to [runner manager machine](https://about.gitlab.com/handbook/engineering/development/enablement/systems/distribution/maintenance/build-machines.html#build-runners-gitlab-org).
+1. Sign in to [runner manager machine](https://handbook.gitlab.com/handbook/engineering/infrastructure/core-platform/systems/distribution/maintenance/build-machines/#build-runners-gitlab-org).
 
 1. Run the following command to force a connection between runner and GitLab
 

doc/development/pipelines.md

@@ -250,7 +250,7 @@ run a package build and QA for development purposes. This can be used by
 developers to get a package or Docker image for testing, or to run a full QA
 suite against their MR's changes.
 
-To debug QA failures, refer to the [Investigate QA failures](https://about.gitlab.com/handbook/engineering/quality/quality-engineering/enablement-saas-platforms-qe-team/distribution/#investigate-qa-failures)
+To debug QA failures, refer to the [Investigate QA failures](https://handbook.gitlab.com/handbook/engineering/infrastructure/test-platform/self-managed-platform-team/distribution/#investigate-qa-failures)
 section. This job also generates Allure report, see more information and the demo at [Test Report Generation in Omnibus-GitLab](allure-test-report.md).
 
 This job is run only on [Development repository](https://gitlab.com/gitlab-org/omnibus-gitlab) and [Security mirror](https://gitlab.com/gitlab-org/security/omnibus-gitlab) on branch

doc/release/index.md

@@ -143,7 +143,7 @@ successful builds.
 
 ### Updating cloud images
 
-The cloud image release process is documented here: <https://about.gitlab.com/handbook/alliances/cloud-images/>.
+The cloud image release process is documented here: <https://handbook.gitlab.com/handbook/alliances/cloud-images/>.
 
 New image are released when:
 

doc/settings/microsoft_graph_mailer.md

@@ -1,7 +1,7 @@
 ---
 stage: Manage
 group: Authentication and Authorization
-info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#designated-technical-writers
+info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://handbook.gitlab.com/handbook/product/ux/technical-writing/#designated-technical-writers
 ---
 
 # Microsoft Graph Mailer settings