diff --git a/docs/dip-2.markdown b/docs/dip-2.markdown
--- a/docs/dip-2.markdown
+++ b/docs/dip-2.markdown
@@ -13,6 +13,7 @@
 * title -- text field.
 * text -- text field.
 * pub-time -- timestamp (TBD: Define format).
+* version -- when post content changes, version should be incremented.
 
 # 2.2 Optional fields #