diff --git a/MQTTKit/MQTTKit.h b/MQTTKit/MQTTKit.h
index 14be2b2..66d2032 100644
--- a/MQTTKit/MQTTKit.h
+++ b/MQTTKit/MQTTKit.h
@@ -7,20 +7,20 @@
 //  Copyright 2012 Nicholas Humfrey. All rights reserved.
 //
 
-typedef enum MQTTConnectionReturnCode : NSUInteger {
+typedef NS_ENUM(NSUInteger, MQTTConnectionReturnCode) {
     ConnectionAccepted,
     ConnectionRefusedUnacceptableProtocolVersion,
     ConnectionRefusedIdentiferRejected,
     ConnectionRefusedServerUnavailable,
     ConnectionRefusedBadUserNameOrPassword,
     ConnectionRefusedNotAuthorized
-} MQTTConnectionReturnCode;
+};
 
-typedef enum MQTTQualityOfService : NSUInteger {
+typedef NS_ENUM(NSUInteger, MQTTQualityOfService) {
     AtMostOnce,
     AtLeastOnce,
     ExactlyOnce
-} MQTTQualityOfService;
+};
 
 #pragma mark - MQTT Message
 
diff --git a/MQTTKit/MQTTKit.m b/MQTTKit/MQTTKit.m
index e1b9951..f65f1c1 100644
--- a/MQTTKit/MQTTKit.m
+++ b/MQTTKit/MQTTKit.m
@@ -272,7 +272,7 @@ - (void)setWillData:(NSData *)payload
              retain:(BOOL)retain
 {
     const char* cstrTopic = [willTopic cStringUsingEncoding:NSUTF8StringEncoding];
-    mosquitto_will_set(mosq, cstrTopic, payload.length, payload.bytes, willQos, retain);
+    mosquitto_will_set(mosq, cstrTopic, (int)payload.length, payload.bytes, willQos, retain);
 }
 
 - (void)setWill:(NSString *)payload
@@ -303,7 +303,7 @@ - (void)publishData:(NSData *)payload
         [self.publishHandlers setObject:completionHandler forKey:[NSNumber numberWithInt:0]];
     }
     int mid;
-    mosquitto_publish(mosq, &mid, cstrTopic, payload.length, payload.bytes, qos, retain);
+    mosquitto_publish(mosq, &mid, cstrTopic, (int)payload.length, payload.bytes, qos, retain);
     if (completionHandler) {
         if (qos == 0) {
             completionHandler(mid);
diff --git a/libmosquitto/logging_mosq.c b/libmosquitto/logging_mosq.c
index de0ba3b..38150b4 100644
--- a/libmosquitto/logging_mosq.c
+++ b/libmosquitto/logging_mosq.c
@@ -39,7 +39,7 @@ int _mosquitto_log_printf(struct mosquitto *mosq, int priority, const char *fmt,
 {
 	va_list va;
 	char *s;
-	int len;
+	size_t len;
 
 	assert(mosq);
 	assert(fmt);
diff --git a/libmosquitto/mosquitto.c b/libmosquitto/mosquitto.c
index a31f277..fcd0dfb 100644
--- a/libmosquitto/mosquitto.c
+++ b/libmosquitto/mosquitto.c
@@ -80,7 +80,7 @@ int mosquitto_lib_init(void)
 	struct timeval tv;
 
 	gettimeofday(&tv, NULL);
-	srand(tv.tv_sec*1000 + tv.tv_usec/1000);
+	srand((unsigned int)(tv.tv_sec*1000 + tv.tv_usec/1000));
 #endif
 
 	_mosquitto_net_init();
@@ -898,7 +898,7 @@ int mosquitto_loop_forever(struct mosquitto *mosq, int timeout, int max_packets)
 #ifdef WIN32
 			Sleep(reconnect_delay*1000);
 #else
-			sleep(reconnect_delay);
+			sleep((unsigned int)reconnect_delay);
 #endif
 
 			pthread_mutex_lock(&mosq->state_mutex);
@@ -1143,7 +1143,7 @@ const char *mosquitto_connack_string(int connack_code)
 
 int mosquitto_sub_topic_tokenise(const char *subtopic, char ***topics, int *count)
 {
-	int len;
+	size_t len;
 	int hier_count = 1;
 	int start, stop;
 	int hier;
diff --git a/libmosquitto/send_client_mosq.c b/libmosquitto/send_client_mosq.c
index 2920256..083a6ef 100644
--- a/libmosquitto/send_client_mosq.c
+++ b/libmosquitto/send_client_mosq.c
@@ -45,7 +45,7 @@ POSSIBILITY OF SUCH DAMAGE.
 int _mosquitto_send_connect(struct mosquitto *mosq, uint16_t keepalive, bool clean_session)
 {
 	struct _mosquitto_packet *packet = NULL;
-	int payloadlen;
+	size_t payloadlen;
 	uint8_t will = 0;
 	uint8_t byte;
 	int rc;
@@ -72,7 +72,7 @@ int _mosquitto_send_connect(struct mosquitto *mosq, uint16_t keepalive, bool cle
 	}
 
 	packet->command = CONNECT;
-	packet->remaining_length = 12+payloadlen;
+	packet->remaining_length = (uint32_t)(12+payloadlen);
 	rc = _mosquitto_packet_alloc(packet);
 	if(rc){
 		_mosquitto_free(packet);
@@ -152,7 +152,7 @@ int _mosquitto_send_subscribe(struct mosquitto *mosq, int *mid, bool dup, const
 	packet = _mosquitto_calloc(1, sizeof(struct _mosquitto_packet));
 	if(!packet) return MOSQ_ERR_NOMEM;
 
-	packetlen = 2 + 2+strlen(topic) + 1;
+	packetlen = 2 + 2+(uint32_t)strlen(topic) + 1;
 
 	packet->command = SUBSCRIBE | (dup<<3) | (1<<1);
 	packet->remaining_length = packetlen;
@@ -197,7 +197,7 @@ int _mosquitto_send_unsubscribe(struct mosquitto *mosq, int *mid, bool dup, cons
 	packet = _mosquitto_calloc(1, sizeof(struct _mosquitto_packet));
 	if(!packet) return MOSQ_ERR_NOMEM;
 
-	packetlen = 2 + 2+strlen(topic);
+	packetlen = 2 + 2+(uint32_t)strlen(topic);
 
 	packet->command = UNSUBSCRIBE | (dup<<3) | (1<<1);
 	packet->remaining_length = packetlen;
diff --git a/libmosquitto/send_mosq.c b/libmosquitto/send_mosq.c
index 1836ce9..1d38f7a 100644
--- a/libmosquitto/send_mosq.c
+++ b/libmosquitto/send_mosq.c
@@ -254,7 +254,7 @@ int _mosquitto_send_simple_command(struct mosquitto *mosq, uint8_t command)
 int _mosquitto_send_real_publish(struct mosquitto *mosq, uint16_t mid, const char *topic, uint32_t payloadlen, const void *payload, int qos, bool retain, bool dup)
 {
 	struct _mosquitto_packet *packet = NULL;
-	int packetlen;
+	size_t packetlen;
 	int rc;
 
 	assert(mosq);
@@ -267,7 +267,7 @@ int _mosquitto_send_real_publish(struct mosquitto *mosq, uint16_t mid, const cha
 
 	packet->mid = mid;
 	packet->command = PUBLISH | ((dup&0x1)<<3) | (qos<<1) | retain;
-	packet->remaining_length = packetlen;
+	packet->remaining_length = (uint32_t)packetlen;
 	rc = _mosquitto_packet_alloc(packet);
 	if(rc){
 		_mosquitto_free(packet);
diff --git a/libmosquitto/util_mosq.c b/libmosquitto/util_mosq.c
index cdb5d1d..26da15f 100644
--- a/libmosquitto/util_mosq.c
+++ b/libmosquitto/util_mosq.c
@@ -213,7 +213,7 @@ int _mosquitto_topic_wildcard_len_check(const char *str)
 int mosquitto_topic_matches_sub(const char *sub, const char *topic, bool *result)
 {
 	char *local_sub, *local_topic;
-	int slen, tlen;
+	size_t slen, tlen;
 	int spos, tpos;
 	int rc;
 	bool multilevel_wildcard = false;