diff --git a/spec/latest/index.bs b/spec/latest/index.bs
index d8e581b..bead91b 100644
--- a/spec/latest/index.bs
+++ b/spec/latest/index.bs
@@ -1,5 +1,5 @@
 <pre class='metadata'>
-Title: Binary Sparse Format Specification
+Title: Binary Sparse Format Specification Version 0.1
 Shortname: binsparse
 Level: 1
 Status: LS-COMMIT
@@ -61,6 +61,7 @@ and 12 columns, containing float32 values, along with user-defined attributes.
 ```json
 {
   "binsparse": {
+    "version": "0.1",
     "format": "CSC",
     "shape": [10, 12],
     "data_types": {
@@ -76,6 +77,14 @@ and 12 columns, containing float32 values, along with user-defined attributes.
 
 </div>
 
+Version {#key_version}
+----------------------
+
+Version indicates the version of the Binsparse specification used here.
+This is a two digit specifier of the form `major.minor`.
+Any minor updates should be backwards compatible with the previous version, e.g. must be a superset of the previous versions within the major release series.
+Major versions may break backwards compatibility.
+
 Shape {#key_shape}
 ------------------
 
@@ -385,6 +394,7 @@ Example of a CSR Matrix whose values are all 7.
 
 ```json
 {
+  "version": "0.1",
   "format": "CSR",
   "shape": [5, 5],
   "data_types": {
@@ -521,6 +531,7 @@ Example of a symmetric CSR matrix.
 
 ```json
 {
+  "version": "0.1",
   "format": "CSR",
   "shape": [5, 5],
   "structure": "symmetric_lower",