diff --git a/src/ckpool.c b/src/ckpool.c
index 4e85521e..be13551e 100644
--- a/src/ckpool.c
+++ b/src/ckpool.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2017 Con Kolivas
+ * Copyright 2014-2018 Con Kolivas
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the Free
@@ -980,7 +980,7 @@ bool send_json_msg(connsock_t *cs, const json_t *json_msg)
 
 /* Decode a string that should have a json message and return just the contents
  * of the result key or NULL. */
-static json_t *json_result(json_t *val)
+json_t *json_result(json_t *val)
 {
 	json_t *res_val = NULL, *err_val;
 
@@ -1005,7 +1005,7 @@ static json_t *json_result(json_t *val)
 }
 
 /* Return the error value if one exists */
-static json_t *json_errval(json_t *val)
+json_t *json_errval(json_t *val)
 {
 	json_t *err_val = json_object_get(val, "error");
 
diff --git a/src/ckpool.h b/src/ckpool.h
index 51ab760a..e519176e 100644
--- a/src/ckpool.h
+++ b/src/ckpool.h
@@ -371,6 +371,8 @@ json_t *json_rpc_call(connsock_t *cs, const char *rpc_req);
 json_t *json_rpc_response(connsock_t *cs, const char *rpc_req);
 void json_rpc_msg(connsock_t *cs, const char *rpc_req);
 bool send_json_msg(connsock_t *cs, const json_t *json_msg);
+json_t *json_result(json_t *val);
+json_t *json_errval(json_t *val);
 json_t *json_msg_result(const char *msg, json_t **res_val, json_t **err_val);
 
 bool json_get_string(char **store, const json_t *val, const char *res);
diff --git a/src/generator.c b/src/generator.c
index 61cf4464..17c1130f 100644
--- a/src/generator.c
+++ b/src/generator.c
@@ -115,6 +115,8 @@ struct proxy_instance {
 	int nonce1len;
 	int nonce2len;
 
+	uint32_t version_mask;
+
 	tv_t last_message;
 
 	double diff;
@@ -1317,6 +1319,35 @@ static void send_notify(ckpool_t *ckp, proxy_instance_t *proxi, notify_instance_
 	send_diff(ckp, proxi);
 }
 
+static void parse_configure(ckpool_t *ckp, proxy_instance_t *proxy, json_t *val)
+{
+	bool vroll = false;
+	json_t *res_val;
+	const char *buf;
+
+	res_val = json_result(val);
+	if (!res_val) {
+		LOGDEBUG("Failed to find result response to mining.configure from proxy %d:%s",
+			 proxy->id, proxy->url);
+		return;
+	}
+	vroll = json_is_true(json_object_get(res_val, "version-rolling"));
+	if (!vroll) {
+		LOGINFO("No version rolling from compatible proxy %d:%s", proxy->id,
+			proxy->url);
+		return;
+	}
+	buf = json_string_value(json_object_get(res_val, "version-rolling.mask"));
+	if (!buf || !strlen(buf)) {
+		LOGNOTICE("Invalid version-rolling.mask from proxy %d:%s", proxy->id,
+			  proxy->url);
+		return;
+	}
+	sscanf(buf, "%x", &proxy->version_mask);
+	LOGINFO("Got vmask %s from proxy %d:%d %s", buf, proxy->id, proxy->subid, proxy->url);
+	stratum_set_proxy_vmask(ckp, proxy->id, proxy->subid, proxy->version_mask);
+}
+
 static bool parse_method(ckpool_t *ckp, proxy_instance_t *proxi, const char *msg)
 {
 	json_t *val = NULL, *method, *err_val, *params;
@@ -1346,6 +1377,9 @@ static bool parse_method(ckpool_t *ckp, proxy_instance_t *proxi, const char *msg
 		if (strstr(msg, "mining.suggest")) {
 			LOGINFO("Unhandled suggest_diff from proxy %d:%s", proxi->id, proxi->url);
 			ret = true;
+		} else if (strstr(msg, "version-rolling")) {
+			parse_configure(ckp, proxi, val);
+			ret = true;
 		} else
 			LOGDEBUG("Failed to find method in json for parse_method");
 		goto out;
@@ -2020,6 +2054,30 @@ static void suggest_diff(ckpool_t *ckp, connsock_t *cs, proxy_instance_t *proxy)
 	 * if it fails upstream. */
 }
 
+static void request_configure(ckpool_t *ckp, connsock_t *cs, proxy_instance_t *proxy)
+{
+	json_t *req;
+	bool ret;
+
+	JSON_CPACK(req, "{s:i,s:s, s:[]}",
+		        "id", 40,
+		        "method", "mining.configure",
+		        "params");
+	ret = send_json_msg(cs, req);
+	json_decref(req);
+	if (!ret) {
+		LOGNOTICE("Proxy %d:%d %s failed to send message in request_configure",
+			  proxy->id, proxy->subid, proxy->url);
+		if (cs->fd > 0) {
+			epoll_ctl(proxy->epfd, EPOLL_CTL_DEL, cs->fd, NULL);
+			Close(cs->fd);
+		}
+	}
+	/* Response will be parsed by receiver since response can be wildly
+	 * variable. */
+}
+
+
 /* Upon failing connnect, subscribe, or auth, back off on the next attempt.
  * This function should be called on the parent proxy */
 static void proxy_backoff(proxy_instance_t *proxy)
@@ -2104,6 +2162,9 @@ static bool proxy_alive(ckpool_t *ckp, proxy_instance_t *proxi, connsock_t *cs,
 		proxy_backoff(parent);
 		goto out;
 	}
+	/* Put a request for mining configure to see if the upstream pool
+	 * supports version_mask */
+	request_configure(ckp, cs, proxi);
 	parent->auth_status = STATUS_SUCCESS;
 	proxi->authorised = ret = true;
 	parent->backoff = 0;
diff --git a/src/stratifier.c b/src/stratifier.c
index ca4fa258..0beea46a 100644
--- a/src/stratifier.c
+++ b/src/stratifier.c
@@ -309,6 +309,8 @@ struct proxy_base {
 	bool subscribed;
 	bool notified;
 
+	uint32_t version_mask;
+
 	int64_t clients; /* Incrementing client count */
 	int64_t max_clients; /* Maximum number of clients per subproxy */
 	int64_t bound_clients; /* Currently actively bound clients */
@@ -3047,6 +3049,15 @@ out:
 	json_decref(val);
 }
 
+void stratum_set_proxy_vmask(ckpool_t *ckp, int id, int subid, uint32_t version_mask)
+{
+	proxy_t *proxy;
+
+	proxy = existing_subproxy(ckp->sdata, id, subid);
+	proxy->version_mask = version_mask;
+	LOGWARNING("Stratum Proxy %d:%d had version mask set to %x", id, subid, version_mask);
+}
+
 static void stratum_send_diff(sdata_t *sdata, const stratum_instance_t *client);
 
 static void update_diff(ckpool_t *ckp, const char *cmd)
@@ -5708,6 +5719,20 @@ static void stratum_send_diff(sdata_t *sdata, const stratum_instance_t *client)
 	stratum_add_send(sdata, json_msg, client->id, SM_DIFF);
 }
 
+#if 0
+/* Needs to be entered with client holding a ref count. */
+static void stratum_send_version_mask(sdata_t *sdata, const stratum_instance_t *client)
+{
+	char version_str[12];
+	json_t *json_msg;
+
+	sprintf(version_str, "%08x", client->ckp->version_mask);
+	JSON_CPACK(json_msg, "{s[s]soss}", "params", version_str, "id", json_null(),
+		   "method", "mining.set_version_mask");
+	stratum_add_send(sdata, json_msg, client->id, SM_VERSIONMASK);
+}
+#endif
+
 /* Needs to be entered with client holding a ref count. */
 static void stratum_send_message(sdata_t *sdata, const stratum_instance_t *client, const char *msg)
 {
diff --git a/src/stratifier.h b/src/stratifier.h
index cc201890..1809c023 100644
--- a/src/stratifier.h
+++ b/src/stratifier.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2017 Con Kolivas
+ * Copyright 2014-2018 Con Kolivas
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the Free
@@ -86,6 +86,7 @@ struct genwork {
 	json_t *json; /* getblocktemplate json */
 };
 
+void stratum_set_proxy_vmask(ckpool_t *ckp, int id, int subid, uint32_t version_mask);
 void parse_remote_txns(ckpool_t *ckp, const json_t *val);
 #define parse_upstream_txns(ckp, val) parse_remote_txns(ckp, val)
 void parse_upstream_auth(ckpool_t *ckp, json_t *val);