diff --git a/schemas/scanbarycentre-README.md b/schemas/scanbarycentre-README.md
index 89c1ce6..9cea06e 100644
--- a/schemas/scanbarycentre-README.md
+++ b/schemas/scanbarycentre-README.md
@@ -27,6 +27,34 @@ senders SHOULD include any defined in the schema if it's in the source data.
 Please read [horizons and odyssey flags](../docs/Developers.md#horizons-and-odyssey-flags)
 in the Developers' documentation.
 
+#### gameversion
+You **MUST** always add this field **to the header object**.
+
+1. If you are using Journal files directly then you **MUST** use the value
+  of the `gameversion` element from the`Fileheader` event.
+2. If you are using the CAPI `/journal` endpoint to retrieve and process
+  Journal events then:
+   1. You will not have `Fileheader` available.
+   2. If `gameversion` is present in the `LoadGame` event, as in 4.0 clients,
+     use its value.
+   3. If `LoadGame` does not have a `gameversion` element, as with 3.8 Horizons
+     clients (up to at least `3.8.0.407`), you **MUST** set `gameversion`, but 
+     with the value `"CAPI"`.
+
+#### gamebuild
+You **MUST** always add this field **to the header object**.
+
+1. If you are using Journal files directly then you **MUST** use the value
+   of the `build` value from the`Fileheader` event.
+2. If you are using the CAPI `/journal` endpoint to retrieve and process
+   Journal events then:
+    1. You will not have `Fileheader` available.
+    2. If `build` is present in the `LoadGame` event, as in 4.0 clients, use
+      its value.
+    3. If `LoadGame` does not have a `build` element, as with 3.8 Horizons
+       clients (up to at least `3.8.0.407`), you **MUST** set `gamebuild`, but
+       with the value `"CAPI"`.
+
 #### StarPos
 You MUST add a `StarPos` array containing the system co-ordinates from the
 last `FSDJump`, `CarrierJump`, or `Location` event.
diff --git a/schemas/scanbarycentre-v1.0.json b/schemas/scanbarycentre-v1.0.json
index e019326..99df117 100644
--- a/schemas/scanbarycentre-v1.0.json
+++ b/schemas/scanbarycentre-v1.0.json
@@ -16,6 +16,16 @@
                 "uploaderID": {
                     "type"          : "string"
                 },
+                "gameversion": {
+                    "type"          : "string",
+                    "minLength"     : 1,
+                    "description"   : "From Fileheader event if available, else LoadGame if available there."
+                },
+                "gamebuild": {
+                    "type"          : "string",
+                    "minLength"     : 1,
+                    "description"   : "The `build` value from a Fileheader event if available, else LoadGame if available there."
+                },
                 "softwareName": {
                     "type"          : "string"
                 },