diff --git a/src/stratifier.c b/src/stratifier.c
index 83f5b1c1..bbced5c1 100644
--- a/src/stratifier.c
+++ b/src/stratifier.c
@@ -232,7 +232,7 @@ struct stratum_instance {
 
 	char address[INET6_ADDRSTRLEN];
 	bool authorised;
-	bool subscribed;
+	bool invalid;
 	bool idle;
 	bool notified_idle;
 
@@ -1245,8 +1245,9 @@ static void new_enonce1(stratum_instance_t *client)
 }
 
 /* Extranonce1 must be set here */
-static json_t *parse_subscribe(stratum_instance_t *client, int64_t client_id, json_t *params_val)
+static json_t *parse_subscribe(int64_t client_id, json_t *params_val)
 {
+	stratum_instance_t *client = NULL;
 	bool old_match = false;
 	int arr_size;
 	json_t *ret;
@@ -1255,6 +1256,15 @@ static json_t *parse_subscribe(stratum_instance_t *client, int64_t client_id, js
 	if (unlikely(!json_is_array(params_val)))
 		return json_string("params not an array");
 
+	ck_rlock(&instance_lock);
+	client = __instance_by_id(client_id);
+	ck_runlock(&instance_lock);
+
+	if (unlikely(!client)) {
+		LOGERR("Failed to find client id %d in hashtable!", client_id);
+		return NULL;
+	}
+
 	if (unlikely(!current_workbase))
 		return json_string("Initialising");
 
@@ -1299,8 +1309,6 @@ static json_t *parse_subscribe(stratum_instance_t *client, int64_t client_id, js
 			n2len);
 	ck_runlock(&workbase_lock);
 
-	client->subscribed = true;
-
 	return ret;
 }
 
@@ -2124,20 +2132,25 @@ static void parse_method(const int64_t client_id, json_t *id_val, json_t *method
 	 * the json item for id_val as is for the response. */
 	method = json_string_value(method_val);
 	if (cmdmatch(method, "mining.subscribe")) {
-		json_t *val, *result_val = parse_subscribe(client, client_id, params_val);
+		json_t *val, *result_val = parse_subscribe(client_id, params_val);
 
+		if (unlikely(!result_val))
+			return;
 		val = json_object();
 		json_object_set_new_nocheck(val, "result", result_val);
 		json_object_set_nocheck(val, "id", id_val);
 		json_object_set_new_nocheck(val, "error", json_null());
 		stratum_add_send(val, client_id);
-		if (likely(client->subscribed))
-			update_client(client, client_id);
+		if (unlikely(!json_is_true(result_val))) {
+			client->invalid = true;
+			return;
+		}
+		update_client(client, client_id);
 		return;
 	}
 
-	if (unlikely(!client->subscribed)) {
-		LOGINFO("Dropping unsubscribed client %d", client->id);
+	if (unlikely(client->invalid)) {
+		LOGINFO("Dropping invalidated client %d", client->id);
 		snprintf(buf, 255, "dropclient=%ld", client->id);
 		send_proc(client->ckp->connector, buf);
 		drop_client(client->id);