diff --git a/.github/actions/action-zephyr/Dockerfile b/.github/actions/action-zephyr/Dockerfile
index ff3a6ac..1ed1a93 100644
--- a/.github/actions/action-zephyr/Dockerfile
+++ b/.github/actions/action-zephyr/Dockerfile
@@ -4,7 +4,7 @@
 # SPDX-License-Identifier: Apache-2.0
 #
 
-FROM bcdevices/zephyr-west:zephyr-2.3.0-0
+FROM bcdevices/zephyr-west:zephyr-2.4.0-0
 
 LABEL "com.github.actions.name"="Zephyr build"
 LABEL "com.github.actions.description"="Build Zephyr project"
diff --git a/Dockerfile b/Dockerfile
index f1c8de4..7a43223 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -4,7 +4,7 @@
 # SPDX-License-Identifier: Apache-2.0
 #
 
-FROM bcdevices/zephyr-west:zephyr-2.3.0-0
+FROM bcdevices/zephyr-west:zephyr-2.4.0-0
 
 WORKDIR /usr/src/
 ## Copy everything (use .dockerignore to exclude)
diff --git a/Makefile b/Makefile
index 914cad4..4f514bc 100644
--- a/Makefile
+++ b/Makefile
@@ -72,8 +72,8 @@ SERVO_MOTOR_TARGETS := $(patsubst %,build.%/servo_motor/zephyr/zephyr.hex,$(BOAR
 SHELL_TARGETS := $(patsubst %,build.%/shell/zephyr/zephyr.hex,$(BOARDS_COMMON))
 
 ZEPHYR_SYSROOT := /usr/src/zephyrproject/zephyr
-#ZEPHYR_SYSROOT := /usr/src/zephyr-2.3.0/zephyr
-ZEPHYR_USRROOT := $(HOME)/src/zephyr-2.3.0/zephyr
+#ZEPHYR_SYSROOT := /usr/src/zephyr-2.4.0/zephyr
+ZEPHYR_USRROOT := $(HOME)/src/zephyr-2.4.0/zephyr
 
 build.%/blinky/zephyr/zephyr.hex:
 	mkdir -p build.$*/blinky
diff --git a/app/prj.conf b/app/prj.conf
index f086435..e2ae64c 100644
--- a/app/prj.conf
+++ b/app/prj.conf
@@ -1,7 +1,7 @@
 CONFIG_BT=y
 CONFIG_BT_PERIPHERAL=y
-CONFIG_BT_GATT_DIS=y
-CONFIG_BT_GATT_DIS_PNP=n
+CONFIG_BT_DIS=y
+CONFIG_BT_DIS_PNP=n
 CONFIG_BT_DEVICE_NAME="LY10ZEPH"
 CONFIG_STDOUT_CONSOLE=y
 CONFIG_I2C=y
diff --git a/app/src/app_ble.c b/app/src/app_ble.c
index 47ec6ca..179d04e 100644
--- a/app/src/app_ble.c
+++ b/app/src/app_ble.c
@@ -18,7 +18,7 @@ static const struct bt_data ad[] = {
     BT_DATA_BYTES(BT_DATA_UUID16_ALL, 0x0a, 0x18),
 };
 
-static void connected(struct bt_conn *conn, u8_t err)
+static void connected(struct bt_conn *conn, uint8_t err)
 {
     if (err) {
 	printk("Connection failed (err %u)\n", err);
@@ -27,7 +27,7 @@ static void connected(struct bt_conn *conn, u8_t err)
     }
 }
 
-static void disconnected(struct bt_conn *conn, u8_t reason)
+static void disconnected(struct bt_conn *conn, uint8_t reason)
 {
     printk("Disconnected (reason %u)\n", reason);
 }
@@ -58,7 +58,7 @@ int app_ble(void)
     printk("Advertising successfully started on the Demo Board\n");
 
     // Get MAC Address
-    u8_t *bd_addr = (u8_t *) ll_addr_get(1, NULL);	// '1' as first parameter indicates we are seeking the 'random' BD address
+    uint8_t *bd_addr = (uint8_t *) ll_addr_get(1, NULL);	// '1' as first parameter indicates we are seeking the 'random' BD address
     printk("Random BD Address: %02x:%02x:%02x:%02x:%02x:%02x\n",
 	   bd_addr[5], bd_addr[4], bd_addr[3],
 	   bd_addr[2], bd_addr[1], bd_addr[0]);
diff --git a/app/src/app_buzzer.c b/app/src/app_buzzer.c
index f1f6885..b98f18e 100644
--- a/app/src/app_buzzer.c
+++ b/app/src/app_buzzer.c
@@ -27,9 +27,9 @@
 #define PWM_CHANNEL 0
 #endif
 
-static u32_t period = PERIOD_INIT;
+static uint32_t period = PERIOD_INIT;
 
-static u32_t note_periods[] = {
+static uint32_t note_periods[] = {
     1000000U / 988,		/* B */
     1000000U / 880,		/* A */
     1000000U / 784,		/* G */
@@ -43,7 +43,7 @@ static u32_t note_periods[] = {
 
 int app_buzzer_setup(void)
 {
-    struct device *pwm;
+    const struct device *pwm;
 
     pwm = device_get_binding(PWM_LABEL);
     if (NULL == pwm) {
diff --git a/app/src/app_ledstrip.c b/app/src/app_ledstrip.c
index bf6164c..a8d8d1b 100644
--- a/app/src/app_ledstrip.c
+++ b/app/src/app_ledstrip.c
@@ -15,7 +15,7 @@
 #define GPIO_PWR_EN  25
 #define STRIP_NUM_LEDS 4
 
-static struct device *strip;
+static const struct device *strip;
 static size_t ledstrip_counter = 0;
 
 static const struct led_rgb colors[] = {
@@ -45,7 +45,7 @@ const struct led_rgb *color_at(size_t time, size_t i)
 
 int app_ledstrip_setup(void)
 {
-    struct device *gpio_out_dev;
+    const struct device *gpio_out_dev;
     int ret;
 
     gpio_out_dev = device_get_binding(GPIO_OUT_DRV_NAME);
diff --git a/app/src/app_sensor.c b/app/src/app_sensor.c
index 82113e1..b5c2f4b 100644
--- a/app/src/app_sensor.c
+++ b/app/src/app_sensor.c
@@ -14,7 +14,7 @@
 int app_sensor_setup(void)
 {
     struct sensor_value temp, hum;
-    struct device *dev = device_get_binding("SHT3XD");
+    const struct device *dev = device_get_binding("SHT3XD");
     int rc;
 
     if (dev == NULL) {