diff --git a/README.md b/README.md
index ea29cb2..25f4805 100644
--- a/README.md
+++ b/README.md
@@ -61,6 +61,7 @@ The main features the RS41ng firmware are:
     * Option to transmit APRS weather reports using readings from an external BMP280/BME280 sensor
   * [Horus 4FSK v1 and v2 modes](https://github.com/projecthorus/horusdemodlib/wiki) that has improved performance compared to APRS or RTTY
     * There is an option to use continuous transmit mode (for either V1 or V2 mode), which helps with receiver frequency synchronization and improves reception.
+    * In order to use Horus 4FSK mode on a flight, you will need to request a new Horus 4FSK payload ID in GitHub according to the instructions at: https://github.com/projecthorus/horusdemodlib/wiki#how-do-i-transmit-it
   * Morse code (CW)
   * JT65/JT9/JT4/FT8/WSPR/FSQ digital modes on HF/VHF amateur radio bands using an external Si5351 clock generator connected to the external I²C bus
   * "Pip" mode, which transmits a short beep generated using CW to indicate presence of the transmitter
@@ -100,6 +101,7 @@ On an external Si5351 clock generator connected to the external I²C bus of the
 * The Horus 4FSK v1 and v2 modes have significantly [improved performance compared to APRS or RTTY](https://github.com/projecthorus/horusdemodlib/wiki).
 * Use [horus-gui](https://github.com/projecthorus/horus-gui) software to receive the 4FSK mode and to submit packets to [Habhub](http://habhub.org/) high-altitude balloon tracking platform.
 * See [horus-gui installation and usage instructions](https://github.com/projecthorus/horusdemodlib/wiki/1.1-Horus-GUI-Reception-Guide-(Windows-Linux-OSX)) and [horusdemodlib](https://github.com/projecthorus/horusdemodlib) library that is responsible for demodulating the signal.
+* In order to use Horus 4FSK mode on a flight, you will need to request a new Horus 4FSK payload ID in GitHub according to the instructions at: https://github.com/projecthorus/horusdemodlib/wiki#how-do-i-transmit-it
 
 ### External sensors
 
diff --git a/src/config.h b/src/config.h
index 4ed60fb..e6b31c5 100644
--- a/src/config.h
+++ b/src/config.h
@@ -217,10 +217,12 @@
 #define HORUS_FREQUENCY_OFFSET_SI4032 0
 
 /**
- * Horus V1 4FSK mode settings
+ * Horus V1 4FSK mode settings (deprecated, please use Horus V2 mode)
  */
 
-// Use Horus payload ID 0 for Horus V1 tests (4FSKTEST)
+// NOTE: Horus 4FSK V1 mode is deprecated in favor of Horus 4FSK V2 mode. All new Horus 4FSK payload IDs are allocated for V2 mode.
+// NOTE: Payload ID 0 (4FSKTEST) is for testing purposes only, and should not be used on an actual flight.
+// Please request a new payload ID in GitHub according to the instructions at: https://github.com/projecthorus/horusdemodlib/wiki#how-do-i-transmit-it
 #define HORUS_V1_PAYLOAD_ID 0
 #define HORUS_V1_BAUD_RATE_SI4032 100
 #define HORUS_V1_BAUD_RATE_SI5351 50
@@ -237,7 +239,8 @@
  * Horus V2 4FSK mode settings
  */
 
-// Use Horus payload ID 256 for Horus V2 tests (4FSKTEST-V2)
+// NOTE: Payload ID 256 (4FSKTEST-V2) is for testing purposes only, and should not be used on an actual flight.
+// Please request a new payload ID in GitHub according to the instructions at: https://github.com/projecthorus/horusdemodlib/wiki#how-do-i-transmit-it
 #define HORUS_V2_PAYLOAD_ID 256
 #define HORUS_V2_BAUD_RATE_SI4032 100
 #define HORUS_V2_BAUD_RATE_SI5351 50