Add feature support signaling

89.md

@@ -129,3 +129,33 @@ Alternatively, users might choose to query directly for `kind:31990` for an even
 ```json
 ["REQ", <id>, '[{ "kinds": [31990], "#k": [<desired-event-kind>], 'authors': [...] }]']
 ```
+
+## Feature Support Signaling
+
+In order to facilitate deprecations of protocol features on nostr, a consensus must be reached _before_ support
+for old features is removed. New features might also benefit from a voting mechanism.
+
+Applications may signal their support of a protocol update using a `kind 36341` event with a `d` tag pointing
+to a url detailing the change, an `a` tag pointing to a `kind 31990` handler, and a `fork` tag. `content` MAY
+be an explanation of the deprecation support.
+
+Valid `fork` values are:
+
+- `hard` - the application fully supports all relevant new features, and has dropped support for deprecated features.
+- `soft` - the application fully supports all relevant new features, but has not dropped support for deprecations.
+- `none` - the application does not support new features, or relies on deprecated features.
+- `never` - the application does not intend to adopt the new standard.
+
+In order to be valid, this event MUST be published by the same key that published the referenced handler.
+
+```json
+{
+  "kind": 36341,
+  "content": "I read and write relays to both kind 3 and kind 10002.",
+  "tags": [
+    ["d", "https://github.com/nostrability/nostrability/issues/10"],
+    ["a", "31990:1743058db7078661b94aaf4286429d97ee5257d14a86d6bfa54cb0482b876fb0:abcd", "<relay-url>"],
+    ["fork", "soft"]
+  ],
+}
+```