diff --git a/Compatibility-issues.md b/Compatibility-issues.md
index e4af8d4..a486983 100644
--- a/Compatibility-issues.md
+++ b/Compatibility-issues.md
@@ -140,7 +140,7 @@ See discussion here: http://feedback.codebender.cc/forums/280538-library-request
 
 ## Arduino Zero and mkr1000 (all boards based on SAMD21)
 
-There is a bug in [Arduino SAMD core](https://github.com/arduino/ArduinoCore-samd) that make `prettyPrintTo()` fail.
+There is a bug in [Arduino SAMD core](https://github.com/arduino/ArduinoCore-samd) that make `prettyPrintTo()` fail (issue [#327](https://github.com/bblanchon/ArduinoJson/issues/327))
 
 It's been fixed on May 27th by [arduino/ArduinoCore-samd@8ef9bb3](https://github.com/arduino/ArduinoCore-samd/commit/8ef9bb3d7bd026b57a8568030d8992644c9b8de8) and [arduino/ArduinoCore-samd@8d0c167](https://github.com/arduino/ArduinoCore-samd/commit/8d0c1674628df1c2c7592f4fc17467c694f5a1be).
 Unfortunately, version 1.6.6 only includes modifications up to May 19th, so the fix is not available through the Arduino Boards Manager.