docs: Add instructions for v4 mainnet upgrade

CONTRIBUTING.md

@@ -15,7 +15,7 @@ You can get help for any questions or problems that you have on through the foll
 - Check if your question/problem is already covered under our documentation sites:
   - [Node / cheqd network](https://docs.cheqd.io/node)
   - [Identity features / SDKs](https://docs.cheqd.io/identity)
-  - [Governance Framework](https://docs.cheqd.io/governance/)
+  - [Governance Framework](https://learn.cheqd.io/governance/start/)
   - [Product Suite & Updates](https://product.cheqd.io)
   - [Learn about cheqd](https://learn.cheqd.io) (basics for general audience)
 - Raise a bug report or feature request using the "Issue" tab on Github

SUMMARY.md

@@ -31,6 +31,7 @@
     * [Upgrade to v2.x (with Ubuntu 24.04 LTS upgrade)](docs/upgrades/upgrade-guides/v2.x-upgrade.md)
     * [Upgrade to v3.x](docs/upgrades/upgrade-guides/v3.x-upgrade.md)
     * [Upgrade to v3.1.x](docs/upgrades/upgrade-guides/v3.1.x-upgrade.md)
+    * [Upgrade to v4.x](docs/upgrades/upgrade-guides/v4.x-upgrade.md)
   * [Creating a software upgrade proposal](docs/upgrades/propose-software-upgrade.md)
   * [Upgrade Process](docs/upgrades/upgrade-process.md)
 

docs/upgrades/README.md

@@ -24,3 +24,4 @@ You can find more details on the actual upgrade process under in our [Upgrade Pr
 - [v2.x Upgrade Guide](upgrade-guides/v2.x-upgrade.md)
 - [v3.x Upgrade Guide](upgrade-guides/v3.x-upgrade.md)
 - [v3.1.x Upgrade Guide](upgrade-guides/v3.1.x-upgrade.md)
+- [v4.x Upgrade Guide](upgrade-guides/v4.x-upgrade.md)

docs/upgrades/upgrade-guides/README.md

@@ -8,3 +8,4 @@ This section lists **previous** software upgrade proposals and specific instruct
 - [v2.x Upgrade Guide](./v2.x-upgrade.md)
 - [v3.x Upgrade Guide](./v3.x-upgrade.md)
 - [v3.1.x Upgrade Guide](./v3.1.x-upgrade.md)
+- [v4.x Upgrade Guide](./v4.x-upgrade.md)

docs/upgrades/upgrade-guides/v4.x-upgrade.md

@@ -0,0 +1,87 @@
+# Introducing the v4.x Protocol Release! 🚀
+
+This upgrade moved cheqd to support **Cosmos SDK v0.50 "Eden"**.
+
+**Cosmos SDK v0.50** is a long-term support version bringing major improvements in performance, developer experience, and modularity. Key features include **ABCI++** for more flexible and efficient consensus and **IAVL 1.0** for faster and more efficient data storage. It also adds **Optimistic Execution** to reduce block times and **Sign Mode Textual** for clearer, more secure transaction signing. This release sets a solid foundation for building faster, more customizable applications on cheqd.
+
+We also **enhanced our DIDs** to support a more flexible **service section**, enabling direct connections to `did:cheqd` DIDs using **DIDComm**. This enhancement brings full cheqd support for **DIDComm endpoint discovery**, making it easier for apps and SDKs like **ACA-Py** and **Credo** to integrate seamless messaging and communication.
+
+You can find more technical details about this upgrade on our [product docs page](https://docs.cheqd.io/product/network/upgrades/2025/4.x).
+
+## Actions that should be taken
+
+- If you're running your node with Cosmovisor and have the binary auto-download feature enabled, **no action is required**.
+
+- In case you run standalone node, you can download the `v4.1.1` binary from our [GitHub Releases page](https://github.com/cheqd/cheqd-node/releases/tag/v4.1.1) and replace them manually on your node.
+
+### ⚠️ Potential errors with binary auto download on Cosmovisor v1.7.1
+
+In case you are running Cosmovisor **v1.7.1**, you might see one potential error when upgrade height is reached.
+Apparently, even though binary is correctly downloaded to `/home/cheqd/.cheqdnode/cosmovisor/upgrades/v4`, the wrong file (the LICENSE file) gets copied to `bin/cheqd-noded`. As a result, your node won’t start after the upgrade.
+
+We suspect this issue is related to upstream Cosmos SDK `x/upgrade` module, and we will investigate separately of this release.
+
+> **ℹ️** This does not present a danger to your node state, but node won't start until you replace binaries.
+
+### 🛠️ How to Prevent This Issue
+
+You have two options:
+
+1) **Re-run [interactive installer](https://raw.githubusercontent.com/cheqd/cheqd-node/refs/heads/main/installer/installer.py)** to make sure you're running Cosmovisor v1.3.0 **before upgrade height is reached**. You will get asked if you want to roll back to Cosmovisor v1.3.0. If you already used interactive installer, just make sure to download the latest one from the link above, before the execution.
+
+2) Alternatively, you can **replace binaries when upgrade height is reached**. You can achieve this with one simple command:
+
+    ```bash
+        cp -P /home/cheqd/.cheqdnode/cosmovisor/upgrades/v4/cheqd-noded /home/cheqd/.cheqdnode/cosmovisor/upgrades/v4/bin/cheqd-noded
+    ```
+
+    To confirm this resolved you issue, just run this:
+
+    ```bash
+        cheqd-noded version
+    ```
+
+### Check Cosmovisor version
+
+To determine whether you need to take any action, check your current Cosmovisor version:
+
+```bash
+    cosmovisor --help
+```
+
+If you're running version **later than v1.3.0**, you will see output like this:
+
+```text
+    Available Commands:
+      add-batch-upgrade Add multiple upgrade binaries at specified heights to cosmovisor
+      add-upgrade       Add APP upgrade binary to cosmovisor
+      completion        Generate the autocompletion script for the specified shell
+      config            Display cosmovisor config.
+      help              Help about any command
+      init              Initialize a cosmovisor daemon home directory.
+      prepare-upgrade   Prepare for the next upgrade
+      run               Run an APP command.
+      show-upgrade-info Display current upgrade-info.json from <app> data directory
+      version           Display cosmovisor and APP version.
+```
+
+**In v1.3.0**, these upgrade-related commands are **not available** (add-batch-upgrade, add-upgrade, prepare-upgrade):
+
+```text
+    Available Commands:
+      completion  Generate the autocompletion script for the specified shell
+      help        Help about any command
+      init        Initializes a cosmovisor daemon home directory.
+      run         Run an APP command.
+      version     Prints the version of Cosmovisor.
+```
+
+To summarize, if you see the second (shorter) output above, you're good to go! ✅
+
+If not, refer back to the previous section and either:
+
+- Roll back to v1.3.0, or
+- Manually replace the binaries at the upgrade height.
+
+If anything's unclear or if you face any additional issues, you can always ask for support on our [#mainnet-operators](https://discord.com/channels/879754359859216394/943432923565154354) Discord channel!
+Also, follow the updates on [our status page](https://status.cheqd.net) and [🔊mainnet-upgrades](https://discord.com/channels/879754359859216394/1394975809139249215) Discord channel.

docs/validator-guide/backup-and-restore.md

@@ -68,7 +68,7 @@ nano <filename>
 
 ### Pre-requisites
 
-Before you get started with this guide, make sure you've [installed HashiCorp Vault CLI](https://developer.hashicorp.com/vault/docs/install) on the validator you want to run backups from.
+Before you get started with this guide, make sure you've [installed HashiCorp Vault CLI](https://developer.hashicorp.com/vault/docs/commands) on the validator you want to run backups from.
 
 You also need a running HashiCorp Vault server cluster you can use to proceed with this guide.