diff --git a/SPEC.md b/SPEC.md
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--- a/SPEC.md
+++ b/SPEC.md
@@ -3,6 +3,8 @@
 This is the semi-formal specification for KDL, including the intended data
 model and the grammar.
 
+This document describes KDL version `1.0.0-pre.0`.
+
 ## Introduction
 
 KDL is a node-oriented document language. Its niche and purpose overlaps with