diff --git a/CHANGELOG.md b/CHANGELOG.md
index 75148c36..64e01bbc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -54,10 +54,14 @@ Versioning](https://semver.org/spec/v2.0.0.html).
   - The `sourceId` field in the `export` GraphQL API is renamed to `sensorId`.
   - The `source` field in the filter parameters of all GraphQL APIs is changed
     to `sensor`.
-- Update the compatibility version of the quic communication modules.
-  - Changed `PEER_VERSION_REQ` to ">=0.23.0,<0.24.0".
+- Update the compatibility version of the quic communication modules, due to the
+  update of giganto-client to 0.21.0.
   - Changed `INGEST_VERSION_REQ` to ">=0.23.0,<0.24.0".
   - Changed `PUBLISH_VERSION_REQ` to ">=0.23.0,<0.24.0".
+- Updated `PEER_VERSION_REQ` to ">=0.23.0,<0.24.0" to ensure compatibility
+  between Giganto instances in the cluster. This change reflects updates to the
+  GraphQL API version and event protocol, which require consistent versions
+  across all nodes.
 
 ### Removed
 
diff --git a/src/peer.rs b/src/peer.rs
index 166d507b..dcc2cd5e 100644
--- a/src/peer.rs
+++ b/src/peer.rs
@@ -40,6 +40,13 @@ use crate::{
     IngestSensors,
 };
 
+// The `PEER_VERSION_REQ` defines the compatibility range for Giganto instances in a cluster.
+// Reasons for updating this version include, but not be limited to:
+// - Updates of GraphQL API version: Since Giganto acts as both a client and server for other
+//   Gigantos in the cluster, maintaining the same API version is necessary for the communication
+//   within the cluster.
+// - Updates of event protocol structures: Any changes to giganto-client's event protocols require
+//   all Gigantos in the cluster to use the same protocol version for compatibility.
 const PEER_VERSION_REQ: &str = ">=0.24.0-alpha.1,<0.25.0";
 const PEER_RETRY_INTERVAL: u64 = 5;