diff --git a/common/features.c b/common/features.c
index ff193c203..ebf14fbdd 100644
--- a/common/features.c
+++ b/common/features.c
@@ -77,6 +77,26 @@ static const struct feature_style feature_styles[] = {
 #endif
 };
 
+struct dependency {
+	size_t depender;
+	size_t must_also_have;
+};
+
+static const struct dependency feature_deps[] = {
+	/* BOLT #9:
+	 * Name                | Description  | Context  | Dependencies  |
+	 *...
+	 * `gossip_queries_ex` | ...          | ...      | `gossip_queries` |
+	 *...
+	 * `payment_secret`    | ...          | ...      | `var_onion_optin` |
+	 *...
+	 * `basic_mpp`         | ...          | ...      | `payment_secret` |
+	 */
+	{ OPT_GOSSIP_QUERIES_EX, OPT_GOSSIP_QUERIES },
+	{ OPT_PAYMENT_SECRET, OPT_VAR_ONION },
+	{ OPT_BASIC_MPP, OPT_PAYMENT_SECRET },
+};
+
 static enum feature_copy_style feature_copy_style(u32 f, enum feature_place p)
 {
 	for (size_t i = 0; i < ARRAY_SIZE(feature_styles); i++) {
@@ -224,6 +244,22 @@ bool feature_negotiated(const struct feature_set *our_features,
 		&& feature_offered(our_features->bits[INIT_FEATURE], f);
 }
 
+bool feature_check_depends(const u8 *their_features,
+			   size_t *depender, size_t *missing_dependency)
+{
+	for (size_t i = 0; i < ARRAY_SIZE(feature_deps); i++) {
+		if (!feature_offered(their_features, feature_deps[i].depender))
+			continue;
+		if (feature_offered(their_features,
+				    feature_deps[i].must_also_have))
+			continue;
+		*depender = feature_deps[i].depender;
+		*missing_dependency = feature_deps[i].must_also_have;
+		return false;
+	}
+	return true;
+}
+
 /**
  * all_supported_features - Check if we support what's being asked
  *
diff --git a/common/features.h b/common/features.h
index f036b798f..9ccd73cc3 100644
--- a/common/features.h
+++ b/common/features.h
@@ -50,6 +50,12 @@ bool feature_offered(const u8 *features, size_t f);
 bool feature_negotiated(const struct feature_set *our_features,
 			const u8 *their_features, size_t f);
 
+/* Features can depend on other features: both must be set!
+ * Sets @depender, @missing_dependency if returns false.
+ */
+bool feature_check_depends(const u8 *their_features,
+			   size_t *depender, size_t *missing_dependency);
+
 /* Return a list of what (init) features we advertize. */
 const char **list_supported_features(const tal_t *ctx,
 				     const struct feature_set *fset);
diff --git a/connectd/connectd.c b/connectd/connectd.c
index d11ac452c..dff9f076a 100644
--- a/connectd/connectd.c
+++ b/connectd/connectd.c
@@ -424,6 +424,7 @@ struct io_plan *peer_connected(struct io_conn *conn,
 	u8 *msg;
 	struct per_peer_state *pps;
 	int unsup;
+	size_t depender, missing;
 
 	if (node_set_get(&daemon->peers, id))
 		return peer_reconnected(conn, daemon, id, addr, cs,
@@ -451,6 +452,14 @@ struct io_plan *peer_connected(struct io_conn *conn,
 		return io_write(conn, msg, tal_count(msg), io_close_cb, NULL);
 	}
 
+	if (!feature_check_depends(their_features, &depender, &missing)) {
+		msg = towire_errorfmt(NULL, NULL,
+				      "Feature %zu requires feature %zu",
+				      depender, missing);
+		msg = cryptomsg_encrypt_msg(tmpctx, cs, take(msg));
+		return io_write(conn, msg, tal_count(msg), io_close_cb, NULL);
+	}
+
 	/* We've successfully connected. */
 	connected_to_peer(daemon, conn, id);