Fix #725: add link to @lnlp's LMIC-node application

Author: terrillmoore

README.md

@@ -16,8 +16,9 @@ see the PDF files in the doc subdirectory.
 
 A separate library, [MCCI `arduino-lorawan`](https://github.com/mcci-catena/arduino-lorawan), provides a higher level, more Arduino-like wrapper which may be useful.
 
-This library requires Arduino IDE version 1.6.6 or above, since it
-requires C99 mode to be enabled by default.
+The examples in this library (apart from the compliance sketch) are somewhat primitive. A very complete cross-platform Arduino application based on the LMIC has been published by Leonel Lopes Parente ([`@lnlp`](https://github.com/lnlp)) as [LMIC-node](https://github.com/lnlp/LMIC-node). That application specifically targets The Things Network.
+
+Although the wrappers in this library are designed to make the LMIC useful in the Arduino environment, the maintainers have tried to be careful to keep the core LMIC code generally useful. For example, I use this library without modification (but with wrappers) on a RISC-V platform in a non-Arduino environment.
 
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