Update README.md

AmalRajUmapathySelvam · web-flow · commit 3473e0943646 · 2019-07-22T16:37:01.000+05:30
diff --git a/README.md b/README.md
@@ -1,2 +1,5 @@
 # How to merge cells in a row in wpf treegrid?
 This example explains how to merge cells in a row in wpf treegrid
+
+Note:
+Supports cell merging from 17.2.0.28 version
