diff --git a/ARM.CMSIS.pdsc b/ARM.CMSIS.pdsc
index be20fe4..e777e60 100644
--- a/ARM.CMSIS.pdsc
+++ b/ARM.CMSIS.pdsc
@@ -8,6 +8,9 @@
   <url>http://www.keil.com/pack/</url>
 
   <releases>
+    <release version="5.2.1-dev4">
+       Active development...
+    </release>
     <release version="5.2.1-dev3" date="2018-01-23">
        CMSIS-NN: 1.0.0
         - Initial contribution of the bare metal Neural Network Library.