Update Adding_New_Messages.md

Author: PaulZC

Adding_New_Messages.md

@@ -1,15 +1,14 @@
 ## How to add new messages to the SparkFun u-blox GNSS Arduino Library
 
-Based on [this issue](https://github.com/sparkfun/SparkFun_u-blox_GNSS_Arduino_Library/issues/97), here is a summary of how to add new messages to the SparkFun u-blox GNSS Arduino Library
-- with full "auto" support (for callbacks, logging, etc.).
+Based on [this issue](https://github.com/sparkfun/SparkFun_u-blox_GNSS_Arduino_Library/issues/97), here is a summary of how to add new messages to the SparkFun u-blox GNSS Arduino Library with full "auto" support (for callbacks, logging, etc.).
 
 Looking at the issue, we see that the library is not supporting the UBX-NAV-PVAT (Navigation Position Velocity Attitude Time solution).
 PVAT is a new message added in version 1.21 of the HPS (High Precision Fusion) firmware and version 33.21 of the F9 Interface Description.
 This makes us wonder if more new messages have been added which should also be included?
 
 ### Step 1: Check the Interface Description for new keys
 
-* Download the latest [interface description](https://www.u-blox.com/sites/default/files/ZED-F9R_ProductSummary_UBX-19048775.pdf) from the [u-blox website](https://www.u-blox.com/en/product/zed-f9r-module#tab-documentation-resources)
+* Download the latest [interface description](https://www.u-blox.com/sites/default/files/F9-HPS-1.21_InterfaceDescription_UBX-21019746.pdf) from the [u-blox website](https://www.u-blox.com/en/product/zed-f9r-module#tab-documentation-resources)
 * Open the interface description in Adobe Acrobat Reader DC (the free version)
 * Do a ```File \ Save as Text...```
 * Save the file in ```Text (Accessible) (*.txt)``` format