diff --git a/docs/Config_Changes.md b/docs/Config_Changes.md
index 707adce6..87cc34da 100644
--- a/docs/Config_Changes.md
+++ b/docs/Config_Changes.md
@@ -6,6 +6,10 @@ All dates in this document are approximate.
 
 # Changes
 
+20190308: The [tmc2660] config section has changed. A new
+sense_resistor config parameter must now be provided. The meaning of
+several of the driver_XXX parameters has changed.
+
 20190228: Users of SPI or I2C on SAMD21 boards must now specify the
 bus pins via a [samd_sercom] config section.