Re-instate node update page

docs/node/install.mdx

@@ -38,6 +38,8 @@ Otherwise, if you wish to run a Massa node from source code, here are the steps
 - set it as default: ```rustup default 1.74.1```
 - check rust version: ```rustc --version```
 - clone this repo: ```git clone https://github.com/massalabs/massa.git```
+- go to the cloned repository: ```cd massa```
+- checkout the latest tag: ```git checkout MAIN.2.1```
 
 ### On Windows
 
@@ -58,6 +60,8 @@ Otherwise, if you wish to run a Massa node from source code, here are the steps
 **Clone the Massa Git Repository**:
 - Open Windows Power Shell
     - Clone the latest distributed version: ```git clone https://github.com/massalabs/massa.git```
+    - Go to the cloned repository: ```cd massa```
+    - Checkout the latest tag: ```git checkout MAIN.2.1```
     - Change default Rust to the following stable version: ```rustup default 1.74.1```
 
 ## My node is installed. What next ?

docs/node/update.mdx

@@ -0,0 +1,31 @@
+---
+id: update
+sidebar_label: Updating a node
+---
+
+# Updating a node
+
+## Update process
+
+The exact update procedure depends on how you previously installed your node.
+
+The basic process goes as follows:
+- Stop your previous node, as running 2 nodes with the same keys will lead to loss of coins
+- Backup your node wallet folders (`massa-node/staking_wallets` and `massa-client/wallets`)
+- If needed, backup you custom config files (`massa-node/config/config.toml` and `massa-client/config/config.toml`)
+- Install your new node by following the [documentation](/docs/node/install).
+- Restore your wallet folders to their respective location
+- If needed, restore your custom configuration
+
+If, during the process, you missed enough block production, your rolls may be automatically sold.
+If that is the case, wait for the coins to get reimbursed automatically (taking ~3 hours), and buy your rolls again.
+
+## Updating the git repository (if installed from sources)
+
+If you installed from sources, you can either re-clone the repo, or you can update your existing repo to the latest release.
+
+In order to update to the latest release, launch a terminal in your current repository, and then run the following commands:
+```shell
+git fetch
+git checkout MAIN.2.1
+```

sidebars.js

@@ -408,6 +408,11 @@ const sidebars = {
       id: "node/all-configs",
       label: "Node and client configuration",
     },
+    {
+      type: "doc",
+      id: "node/update",
+      label: "Updating a node",
+    },
     {
       type: "html",
       value: "<hr/>",