diff --git a/site/content/_index/components/tcp.md b/site/content/_index/components/tcp.md
index 4252dc89d4..e205e6e3c0 100644
--- a/site/content/_index/components/tcp.md
+++ b/site/content/_index/components/tcp.md
@@ -4,7 +4,7 @@ weight = 15
 
 [asset]
   icon = "fas fa-pause"
-  url = "https://github.com/eclipse/californium/tree/master/element-connector-tcp-netty"
+  url = "https://github.com/eclipse/californium/tree/main/element-connector-tcp-netty"
 +++
 
 Experimental CoAP over TCP implementation using netty.io.
diff --git a/site/content/_index/components/tools.md b/site/content/_index/components/tools.md
index b66e71ed5d..6bc0a8a3d4 100644
--- a/site/content/_index/components/tools.md
+++ b/site/content/_index/components/tools.md
@@ -9,5 +9,5 @@ weight = 10
 
 This repository provides CoAP tools that also serve as examples. Use our cf-client to interact with your devices from the command line, or the cf-browser to benefit from the UI. Both share a rich set of CLI arguments, enable to prepare to exchange messages in many different ways.
 
-[cf-client](https://github.com/eclipse/californium.tools/tree/master/cf-client#cf-client),
-[cf-browser](https://github.com/eclipse/californium.tools/tree/master/cf-browser#cf-browser).
+[cf-client](https://github.com/eclipse/californium.tools/tree/main/cf-client#cf-client),
+[cf-browser](https://github.com/eclipse/californium.tools/tree/main/cf-browser#cf-browser).
diff --git a/site/content/_index/connector.md b/site/content/_index/connector.md
index e9459cd73a..3a1e51ecf1 100644
--- a/site/content/_index/connector.md
+++ b/site/content/_index/connector.md
@@ -13,10 +13,10 @@ title = "Element-Connector"
 
 [[buttons]]
   text = "Introduction"
-  url = "https://github.com/eclipse/californium/tree/master/element-connector#element-connector"
+  url = "https://github.com/eclipse/californium/tree/main/element-connector#element-connector"
 [[buttons]]
   text = "Repository"
-  url = "https://github.com/eclipse/californium/tree/master/element-connector"
+  url = "https://github.com/eclipse/californium/tree/main/element-connector"
 +++
 
 The element-connector abstracts from the different transports CoAP can use.
diff --git a/site/content/_index/core.md b/site/content/_index/core.md
index 77d62ef40f..7452b6b202 100644
--- a/site/content/_index/core.md
+++ b/site/content/_index/core.md
@@ -19,7 +19,7 @@ title = "Californium (Cf) Core"
 
 [[buttons]]
   text = "Introduction"
-  url = "https://github.com/eclipse/californium/tree/master/californium-core#californium-cf---coap-core"
+  url = "https://github.com/eclipse/californium/tree/main/californium-core#californium-cf---coap-core"
 [[buttons]]
   text = "Repository"
   url = "https://github.com/eclipse/californium"
diff --git a/site/content/_index/installs/k8s.md b/site/content/_index/installs/k8s.md
index a684871b21..3ea33ee90e 100644
--- a/site/content/_index/installs/k8s.md
+++ b/site/content/_index/installs/k8s.md
@@ -10,6 +10,6 @@ weight = 20
 Californium runs on k8s. Extensions to be used with k8s are provided in the . For simple single pod deployments it supports a Blue/Green update with DTLS graceful restart simply on updating the image. For multiple pod deployments it supports additionally DTLS Connection ID Cluster.<br>
 Unleash the power, prepare for huge numbers of devices and plenty messages.
 
-[k8s module](https://github.com/eclipse/californium/tree/master/cf-utils/cf-cluster#californium-cf---k8s-support),
-[Blue/Green Update with DTLS graceful restart](https://github.com/eclipse/californium/blob/master/cf-utils/cf-cluster/README.md#k8s-bluegreen-update-with-dtls-graceful-restart),
-[DTLS Connection ID Cluster](https://github.com/eclipse/californium/blob/master/cf-utils/cf-cluster/README.md#californium-cf---k8s-built-in-support-for-dtls-connection-id-cluster).
+[k8s module](https://github.com/eclipse/californium/tree/main/cf-utils/cf-cluster#californium-cf---k8s-support),
+[Blue/Green Update with DTLS graceful restart](https://github.com/eclipse/californium/blob/main/cf-utils/cf-cluster/README.md#k8s-bluegreen-update-with-dtls-graceful-restart),
+[DTLS Connection ID Cluster](https://github.com/eclipse/californium/blob/main/cf-utils/cf-cluster/README.md#californium-cf---k8s-built-in-support-for-dtls-connection-id-cluster).
diff --git a/site/content/_index/installs/vm.md b/site/content/_index/installs/vm.md
index 192a556f87..8937ab8a13 100644
--- a/site/content/_index/installs/vm.md
+++ b/site/content/_index/installs/vm.md
@@ -4,13 +4,13 @@ weight = 10
 
 [asset]
   icon = "fas fa-server"
-  url = "https://github.com/eclipse/californium/tree/master/demo-apps/cf-unix-setup#californium-as-old-style-unix-systemd-service"
+  url = "https://github.com/eclipse/californium/tree/main/demo-apps/cf-unix-setup#californium-as-old-style-unix-systemd-service"
 +++
 
 Californium is easy to install as unix systemd service. Instructions for manual installation are provided. It supports DTLS graceful restart providing a unique experience using encryption for the Internet of Things.
 <br>
 For cloud-VMs, using cloudinit makes the installation even easier. Finally, install scripts are provided, which enables you to start your own server within minutes.
 
-[DTLS graceful restart](https://github.com/eclipse/californium/tree/master/demo-apps/cf-extplugtest-server#benchmarks---dtls-graceful-restart),<br>
-[cloudinit](https://github.com/eclipse/californium/tree/master/demo-apps/cf-unix-setup#cloud-init---automatic-cloud-vm-installation), [install scripts](https://github.com/eclipse/californium/tree/master/demo-apps/cf-unix-setup#installation-on-exoscale-cloud).
+[DTLS graceful restart](https://github.com/eclipse/californium/tree/main/demo-apps/cf-extplugtest-server#benchmarks---dtls-graceful-restart),<br>
+[cloudinit](https://github.com/eclipse/californium/tree/main/demo-apps/cf-unix-setup#cloud-init---automatic-cloud-vm-installation), [install scripts](https://github.com/eclipse/californium/tree/main/demo-apps/cf-unix-setup#installation-on-exoscale-cloud).
 
diff --git a/site/content/_index/scandium.md b/site/content/_index/scandium.md
index d3af071582..91778f1dc7 100644
--- a/site/content/_index/scandium.md
+++ b/site/content/_index/scandium.md
@@ -19,11 +19,11 @@ title = "Scandium (Sc)"
 
 [[buttons]]
   text = "Introduction"
-  url = "https://github.com/eclipse/californium/tree/master/scandium-core#scandium-sc---security-for-californium"
+  url = "https://github.com/eclipse/californium/tree/main/scandium-core#scandium-sc---security-for-californium"
 
 [[buttons]]
   text = "Repository"
-  url = "https://github.com/eclipse/californium/tree/master/scandium-core"
+  url = "https://github.com/eclipse/californium/tree/main/scandium-core"
 +++
 
 The Scandium (Sc) sub-module provides security for Californium. It implements DTLS 1.2 to secure your application