diff --git a/src/aht.c b/src/aht.c
index 08e4009..e523ae3 100644
--- a/src/aht.c
+++ b/src/aht.c
@@ -1,3 +1,6 @@
+// SPDX-License-Identifier: MIT
+// SPDX-FileCopyrightText: 2026 A.M. Rowsell <amr@frzn.dev>
+
 #include "aht.h"
 
 #include "hardware/i2c.h"
diff --git a/src/main.c b/src/main.c
index bc623f0..e3e41bf 100644
--- a/src/main.c
+++ b/src/main.c
@@ -18,13 +18,14 @@
  *               the readings to Adafruit IO over MQTT using the Pico W.
  ******************************************************************************/
 
-#include "aht.h"
-#include "bmp.h"
-#include "credentials.h"
-#include "ens.h"
 #include "hardware/gpio.h"
 #include "hardware/i2c.h"
-#include "mqtt.h"
+#include "include/aht.h"
+#include "include/bmp.h"
+#include "include/credentials.h"
+#include "include/ens.h"
+#include "include/mqtt.h"
+#include "include/opt4048.h"
 #include "pico/cyw43_arch.h"
 #include "pico/stdlib.h" // IWYU pragma: keep
 #include <boards/pico_w.h>