diff --git a/crates/ruma-common/Cargo.toml b/crates/ruma-common/Cargo.toml
index 9b83af31..ffa9b112 100644
--- a/crates/ruma-common/Cargo.toml
+++ b/crates/ruma-common/Cargo.toml
@@ -30,6 +30,7 @@ unstable-msc3026 = []
 unstable-msc3930 = []
 unstable-msc3931 = []
 unstable-msc3932 = ["unstable-msc3931"]
+unstable-msc4210 = []
 unstable-unspecified = []
 
 # Allow IDs to exceed 255 bytes.
diff --git a/crates/ruma-common/src/push.rs b/crates/ruma-common/src/push.rs
index 634d367c..47a778c5 100644
--- a/crates/ruma-common/src/push.rs
+++ b/crates/ruma-common/src/push.rs
@@ -487,6 +487,18 @@ impl ConditionalPushRule {
             return false;
         }
 
+        // The old mention rules are disabled when an m.mentions field is present.
+        //
+        // MSC4210 always disables the legacy rules.
+        #[allow(deprecated)]
+        if (self.rule_id == PredefinedOverrideRuleId::RoomNotif.as_ref()
+            || self.rule_id == PredefinedOverrideRuleId::ContainsDisplayName.as_ref()
+            || self.rule_id == PredefinedContentRuleId::ContainsUserName.as_ref())
+            && (event.contains_mentions() || cfg!(feature = "unstable-msc4210"))
+        {
+            return false;
+        }
+
         #[cfg(feature = "unstable-msc3932")]
         {
             // These 3 rules always apply.
@@ -510,15 +522,6 @@ impl ConditionalPushRule {
             }
         }
 
-        // The old mention rules are disabled when an m.mentions field is present.
-        #[allow(deprecated)]
-        if (self.rule_id == PredefinedOverrideRuleId::RoomNotif.as_ref()
-            || self.rule_id == PredefinedOverrideRuleId::ContainsDisplayName.as_ref())
-            && event.contains_mentions()
-        {
-            return false;
-        }
-
         self.conditions.iter().all(|cond| cond.applies(event, context))
     }
 }
diff --git a/crates/ruma-common/src/push/predefined.rs b/crates/ruma-common/src/push/predefined.rs
index 74a4c891..402287c3 100644
--- a/crates/ruma-common/src/push/predefined.rs
+++ b/crates/ruma-common/src/push/predefined.rs
@@ -22,6 +22,7 @@ impl Ruleset {
     pub fn server_default(user_id: &UserId) -> Self {
         Self {
             content: [
+                #[cfg(not(feature = "unstable-msc4210"))]
                 #[allow(deprecated)]
                 PatternedPushRule::contains_user_name(user_id),
             ]
@@ -32,9 +33,11 @@ impl Ruleset {
                 ConditionalPushRule::invite_for_me(user_id),
                 ConditionalPushRule::member_event(),
                 ConditionalPushRule::is_user_mention(user_id),
+                #[cfg(not(feature = "unstable-msc4210"))]
                 #[allow(deprecated)]
                 ConditionalPushRule::contains_display_name(),
                 ConditionalPushRule::is_room_mention(),
+                #[cfg(not(feature = "unstable-msc4210"))]
                 #[allow(deprecated)]
                 ConditionalPushRule::roomnotif(),
                 ConditionalPushRule::tombstone(),
diff --git a/crates/ruma/Cargo.toml b/crates/ruma/Cargo.toml
index 5e012766..689784ba 100644
--- a/crates/ruma/Cargo.toml
+++ b/crates/ruma/Cargo.toml
@@ -270,6 +270,7 @@ unstable-msc4121 = ["ruma-client-api?/unstable-msc4121"]
 unstable-msc4125 = ["ruma-federation-api?/unstable-msc4125"]
 unstable-msc4140 = ["ruma-client-api?/unstable-msc4140"]
 unstable-msc4186 = ["ruma-client-api?/unstable-msc4186"]
+unstable-msc4210 = ["ruma-common/unstable-msc4210"]
 unstable-pdu = ["ruma-events?/unstable-pdu"]
 unstable-unspecified = [
     "ruma-common/unstable-unspecified",