diff --git a/README.md b/README.md
index 1270699..fe09ac2 100644
--- a/README.md
+++ b/README.md
@@ -28,4 +28,4 @@ if (result) {
 ## TODO
 
 * Add script for publishing both human- and machine-readable schemas to
-  https://schemas.kosmos.org
+  https://schema.kosmos.org
diff --git a/schemas/contribution.json b/schemas/contribution.json
index fcea8e0..9c4ee9f 100644
--- a/schemas/contribution.json
+++ b/schemas/contribution.json
@@ -1,5 +1,5 @@
 {
-  "$schema": "https://json-schema.org/draft-04/schema#",
+  "$schema": "https://json-schema.org/draft-07/schema#",
   "id": "https://schema.kosmos.org/Contribution",
   "properties": {
     "@context": {
@@ -26,6 +26,18 @@
       ],
       "type": "object"
     },
+    "date": {
+      "type": "string",
+      "format": "date",
+      "title": "Date",
+      "description": "Date of contribution (RFC 3339 full-date)"
+    },
+    "time": {
+      "type": "string",
+      "format": "time",
+      "title": "Time",
+      "description": "Time of contribution (RFC 3339 full-time)"
+    },
     "kind": {
       "type": "string",
       "title": "Kind",
@@ -56,6 +68,7 @@
   },
   "required": [
     "contributor",
+    "date",
     "kind",
     "description"
   ],
diff --git a/schemas/contributor.json b/schemas/contributor.json
index 7978f7b..544858f 100644
--- a/schemas/contributor.json
+++ b/schemas/contributor.json
@@ -1,5 +1,5 @@
 {
-  "$schema": "https://json-schema.org/draft-04/schema#",
+  "$schema": "https://json-schema.org/draft-07/schema#",
   "id": "https://schema.kosmos.org/Contributor",
   "properties": {
     "@context": {