diff --git a/src/config/client.rs b/src/config/client.rs
index 23f98f7..ad8426d 100644
--- a/src/config/client.rs
+++ b/src/config/client.rs
@@ -11,6 +11,7 @@ use validator::{Validate, ValidationError};
 
 #[derive(Deserialize, Serialize, Validate, Debug)]
 pub struct Config {
+    #[validate(custom(function = "super::ensure_latest_revision"))]
     pub config_revision: Revision,
     #[validate(nested)]
     pub theme: Option<Theme>,
diff --git a/src/config/mod.rs b/src/config/mod.rs
index 065dd60..c9a4a73 100644
--- a/src/config/mod.rs
+++ b/src/config/mod.rs
@@ -4,6 +4,7 @@ pub mod server;
 use clap::ValueEnum;
 use enum_iterator::Sequence;
 use serde_repr::{Deserialize_repr, Serialize_repr};
+use validator::ValidationError;
 
 pub const SERVER_CONFIG_PATH: &str = "config/server.toml";
 pub const CLIENT_CONFIG_PATH: &str = "config/client.toml";
@@ -19,3 +20,10 @@ pub enum Revision {
     /// The first revision number for `config/{server,client}.toml`
     V1,
 }
+
+fn ensure_latest_revision(revision: &Revision) -> Result<(), ValidationError> {
+    match revision.next() {
+        Some(_) => Err(ValidationError::new("not the latest revision")),
+        None => Ok(()),
+    }
+}
diff --git a/src/config/server.rs b/src/config/server.rs
index b4b4d59..b180560 100644
--- a/src/config/server.rs
+++ b/src/config/server.rs
@@ -11,6 +11,7 @@ use validator::Validate;
 
 #[derive(Deserialize, Serialize, Validate, Debug)]
 pub struct Config {
+    #[validate(custom(function = "super::ensure_latest_revision"))]
     pub config_revision: Revision,
     #[validate(nested)]
     pub info: Option<Info>,