diff --git a/docs/architecture.md b/docs/architecture.md
index db33d6836..0ff35565c 100644
--- a/docs/architecture.md
+++ b/docs/architecture.md
@@ -17,4 +17,4 @@ Bitmaps are persisted to disk using a file format very similar to the [Roaring B
 
 ![roaring file format diagram](/img/docs/pilosa-roaring-storage-diagram.png)
 
-All values are little-endian. The first two bytes of the cookie is 12348, to reflect incompatibility with the spec. Container types are NOT inferred from their cardinality as in the spec. Instead, the container type is read directly from the descriptive header.
+All values are little-endian. The first two bytes of the cookie is 12348, to reflect incompatibility with the spec, which uses 12346 or 12347. Container types are NOT inferred from their cardinality as in the spec. Instead, the container type is read directly from the descriptive header.