Add previous tag

01.md

@@ -99,6 +99,8 @@ And also a convention for kind ranges that allow for easier experimentation and
 
 In case of replaceable events with the same timestamp, the event with the lowest id (first in lexical order) should be retained, and the other discarded.
 
+When the `previous` tag exists on a replaceable event relays SHOULD use this id as the id of the version the client wishes to replace, if the id does not match the stored version, relays MUST reject the update.
+
 When answering to `REQ` messages for replaceable events such as `{"kinds":[0],"authors":[<hex-key>]}`, even if the relay has more than one version stored, it SHOULD return just the latest one.
 
 These are just conventions and relay implementations may differ.

91.md

@@ -1,52 +0,0 @@
-NIP-91
-======
-
-EOSE Extensions
----------------
-
-`draft` `optional`
-
-This NIP defines an extension to the EOSE message that allows relays to convey additional information to clients.
-
-## Extended EOSE
-
-An extended EOSE is an EOSE message, with the 2nd parameter being the "extensions object". For example: `["EOSE","example-sub",{"example_ext":"example value"}]`
-
-An EOSE extension is a field in the extensions object. This may contain any value.
-
-Clients MUST NOT rely on relays implementing any extensions.
-
-## Extensions
-
-This NIP defines a set of standard extensions.
-
-### `next_created_at`
-`recommended`
-
-The value of this extension MUST be an integer if present, and should specify the next `until` value the client should use for pagination.
-This MAY be higher or lower than the lowest `created_at`, and the clients SHOULD NOT perform any modifications to this value.
-
-### `cursor`
-
-The value of this extension MUST be a string or `null` if present, and represents a cursor the client can use to paginate this query.
-If the value is `null`, then it indicates that no more events are available for the given set of filters.
-To get more events, the client MUST send a `REQ` with the same filters (except limit, which can be changed), and the `cursor` string
-in the 1st filter with the key `cursor`. Example:
-```jsonc
-< ["REQ", "examplereq1", {"kinds": [1], "limit": 1}, {"authors": ["..."], "limit": 1}]
-> ["EVENT", "examplereq1", ...]
-> ["EOSE", "examplereq1", {"cursor": "example-cursor-string", ...}]
-< ["CLOSE", "examplereq1"]
-< ["REQ", "examplereq2", {"kinds": [1], "limit": 5, "cursor": "example-cursor-string"}, {"authors": ["..."], "limit": 5}]
-> ["EVENT", "examplereq2", ...]
-...
-```
-
-This cursor MUST be valid for the duration of the connection, and MAY be valid in a new connection. A relay may indicate a cursor is no longer valid
-by sending a CLOSED with the prefix `bad-cursor: `.
-
-### `auth_recommended`
-
-The value of this extension MUST be a boolean if present, and indicates if the client should `AUTH` to get more events that match this query.
-This is a less disruptive alternative to `CLOSED` with `auth-required:` for filters that don't explicitly ask for access controlled events,
-but may match them.