docs: document celestia-app v9 operator changes

app/operate/consensus-validators/cli-reference/page.mdx

@@ -2,6 +2,8 @@
 description: Some of the most helpful celestia-app CLI commands.
 ---
 
+import { Callout } from 'nextra/components'
+
 # Helpful CLI commands
 
 View all options:
@@ -36,6 +38,18 @@ Available Commands:
   version             Print the application binary version information
 ```
 
+## Updating node configuration
+
+<Callout type="warning">
+The `celestia-appd update-config` command is deprecated as of v9. Required
+configuration values are now enforced by the binary at startup, so do not add
+this command to new node initialisation or upgrade procedures. It currently
+prints a deprecation warning and will be removed in a future release.
+</Callout>
+
+See the [celestia-app v9 release notes](https://github.com/celestiaorg/celestia-app/blob/v9.0.4/docs/release-notes/release-notes.md#update-config-command-deprecated)
+for details.
+
 ## Creating a wallet
 
 ```sh

app/operate/consensus-validators/consensus-node/page.mdx

@@ -18,7 +18,7 @@ See [hardware requirements](/operate/getting-started/hardware-requirements).
 
 ## Set up a consensus node
 
-The following tutorial is done on an Ubuntu Linux 20.04 (LTS) x64
+The following tutorial is done on an Ubuntu Linux 24.04 (LTS) x64
 instance machine.
 
 <Steps>
@@ -151,14 +151,23 @@ indexer = "kv"
 
 If you want to query the historical state — for example, you might want
 to know the balance of a Celestia wallet at a given height in the past —
-you should run an archive node with `pruning = "nothing"` in your `app.toml`.
-Note that this configuration is resource-intensive and will require
+you should run an archive node. In your `app.toml`, set `pruning = "nothing"`
+to retain application state and `min-retain-blocks = 0` to retain all block
+data. Note that this configuration is resource-intensive and will require
 significant storage:
 
 ```toml
 pruning = "nothing"
+min-retain-blocks = 0
 ```
 
+<Callout type="warning">
+`min-retain-blocks` defaults to `0`. Any non-zero value enables block pruning,
+so archival operators must keep the value at `0`. Changing the value from `0`
+to a non-zero value starts pruning the existing backlog when the node restarts
+and can temporarily increase sync time.
+</Callout>
+
 ### Save on storage requirements
 
 If you want to save on storage requirements, consider using
@@ -199,7 +208,19 @@ By default, a consensus node will sync using block sync; which will request, val
 and execute every block up to the head of the blockchain. This is the most secure
 mechanism yet the slowest (taking up to weeks depending on the height of the blockchain).
 
-There is an [issue](https://github.com/celestiaorg/celestia-app/issues/4370) that prevents recent celestia-app binaries from block syncing Mainnet Beta. As a temporary workaround, you can use celestia-app [v3.0.2](https://github.com/celestiaorg/celestia-app/releases/tag/v3.0.2) to block sync Mainnet Beta until that issue is resolved. After block syncing, please upgrade to the latest version of celestia-app to pick up recent security fixes.
+Starting with celestia-app v9, `verify_data` defaults to `false` in the
+`[blocksync]` section of `config.toml`. This skips re-running `ProcessProposal`
+on historical blocks to improve block sync speed. Blocks are still verified by
+their validator signatures, and normal validation resumes after the node enters
+consensus mode. To restore the pre-v9 behaviour, set:
+
+```toml
+[blocksync]
+verify_data = true
+```
+
+See the [celestia-app v9 release notes](https://github.com/celestiaorg/celestia-app/blob/v9.0.4/docs/release-notes/release-notes.md#block-sync-verify_data-default-changed-to-false)
+for details.
 
 There are two alternatives for quicker syncing.
 

app/operate/consensus-validators/install-celestia-app/page.mdx

@@ -2,7 +2,7 @@
 description: Learn how you can build celestia-app.
 ---
 
-import { Steps, Tabs } from 'nextra/components'
+import { Callout, Steps, Tabs } from 'nextra/components'
 
 # Install celestia-app
 
@@ -24,6 +24,23 @@ Celestia-app officially supports the following architectures:
 
 Only these four architectures are officially tested and supported.
 
+## Linux requirements
+
+<Callout type="warning">
+celestia-app v9 multiplexer binaries require glibc 2.38 or later. Use Ubuntu
+24.04 LTS or an equivalent Linux distribution. Ubuntu 22.04 and older are not
+supported and the binary will fail to start with a glibc version mismatch.
+</Callout>
+
+Check the installed glibc version before installing or upgrading:
+
+```bash
+ldd --version
+```
+
+See the [celestia-app v9 release notes](https://github.com/celestiaorg/celestia-app/blob/v9.0.4/docs/release-notes/release-notes.md#supported-operating-systems)
+for the supported operating system details.
+
 ## Building binary from source
 
 This section of the tutorial assumes you completed the steps in

app/operate/consensus-validators/validator-node/page.mdx

@@ -17,7 +17,7 @@ See [hardware requirements](/operate/getting-started/hardware-requirements).
 
 ## Setting up a validator node
 
-The following tutorial is done on an Ubuntu Linux 20.04 (LTS) x64
+The following tutorial is done on an Ubuntu Linux 24.04 (LTS) x64
 instance machine.
 
 First, follow the instructions on