FEP-7628: Update proposal (#875)

- Changed terminlogy: persona -> subject
- Added `id` to the list of required properties.
- Specified activity audience for push and pull modes.
- Added "Future work" section.
- Improved grammar.
- Removed old .jsonld file

Reviewed-on: https://codeberg.org/fediverse/fep/pulls/875

fep/7628/context.jsonld

@@ -1,12 +0,0 @@
-{
-  "@context": {
-    "movedTo": {
-      "@id": "https://w3id.org/fep/7628#movedTo",
-      "@type": "@id"
-    },
-    "copiedTo": {
-      "@id": "https://w3id.org/fep/7628#copiedTo",
-      "@type": "@id"
-    }
-  }
-}

fep/7628/fep-7628.md

@@ -17,7 +17,7 @@ Migration of followers from one [ActivityPub][ActivityPub] actor to another.
 
 `Move` activity is defined in [Activity Vocabulary](https://www.w3.org/TR/activitystreams-vocabulary/#dfn-move).
 
-Mastodon started using [`Move`](https://docs.joinmastodon.org/spec/activitypub/#Move) activity for migrating accounts [in 2019](https://github.com/mastodon/mastodon/pull/11846). The activity is sent by the old server to actor's followers and actors who receive this activity un-follow the old account and follow the new account.
+Mastodon started using [`Move`](https://docs.joinmastodon.org/spec/activitypub/#Move) activity for migrating accounts [in 2019](https://github.com/mastodon/mastodon/pull/11846). The old account sends this activity to its followers. Actors who receive the activity un-follow the old account and follow the new one.
 
 ## Requirements
 
@@ -25,7 +25,7 @@ The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "S
 
 ## Linked actors
 
-One persona can be represented by one or more actors. Different actors are considered associated with one persona if and only if they are **linked**. Possible ways to link actors:
+One subject can be represented by one or more actors. Different actors are considered associated with one subject if and only if they are **linked**. Possible ways to link actors:
 
 - `alsoKnownAs` property of an actor object. This method is the most popular, it is used by [Mastodon](https://docs.joinmastodon.org/user/moving/#aliases) and many other ActivityPub servers.
 - [FEP-c390][FEP-c390] identity proofs. Actors are linked if they have identity proofs with the same `subject` property.
@@ -33,12 +33,13 @@ One persona can be represented by one or more actors. Different actors are consi
 
 ## Migration
 
-Among actors associated with a persona, there MUST be one **primary** actor. **Migration** of an account means the change of a primary actor.
+Among actors associated with a subject, there MUST be one **primary** actor. **Migration** of an account means the change of a primary actor.
 
 ## Move activity
 
 `Move` activity is used to notify other actors about the migration. It MUST have the following properties:
 
+- `id`: the unique identifier of an activity.
 - `type`: the type of activity MUST be `Move`.
 - `actor`: the actor performing the migration.
 - `object`: the old primary actor ID.
@@ -50,8 +51,8 @@ Upon receiving valid `Move` activity, all actors following `object` MAY un-follo
 
 This activity comes in two sub-types:
 
-1. `Move` sent by the old actor (**push mode**). In this case, the old server needs to be online.
-2. `Move` sent by the new actor (**pull mode**). In this case, the old server doesn't need to be online, but the person using the actor needs to have a reserve copy of the follower list.
+1. `Move` sent by the old actor (**push mode**). In this case, the old server needs to be online. The activity MUST be addressed to the followers of the old actor.
+2. `Move` sent by the new actor (**pull mode**). In this case, the old server doesn't need to be online, but the person using the actor needs to have a reserve copy of the follower list. The activity MUST be addressed to the followers of the new actor.
 
 Example (activity subtype 1, push mode):
 
@@ -85,9 +86,9 @@ Example (activity subtype 2, pull mode):
 
 ## `movedTo` and `copiedTo` properties
 
-If previous primary actor was deactivated after migration, it MUST have `movedTo` property containing the ID of the new primary actor. Publishers SHOULD NOT deliver activities to actor's inbox if `movedTo` property is present.
+If the old primary actor was deactivated after migration, it MUST have a `movedTo` property containing the ID of the new primary actor. Publishers SHOULD NOT deliver activities to actor's inbox if `movedTo` property is present.
 
-If previous primary actor is not deactivated, `copiedTo` property MUST be used.
+If the old primary actor is not deactivated, the `copiedTo` property MUST be used.
 
 After adding the `movedTo` or `copiedTo` property, the actor SHOULD notify its followers about the change by publishing an `Update` activity.
 
@@ -108,6 +109,13 @@ After adding the `movedTo` or `copiedTo` property, the actor SHOULD notify its f
 </dd>
 </dl>
 
+## Future work
+
+The `Move` activity described in this document migrates followers, but not other user data. To address this shortcoming, other mechanisms have been proposed:
+
+- [FEP-ef61: Portable Objects](https://codeberg.org/fediverse/fep/src/branch/main/fep/ef61/fep-ef61.md)
+- [FEP-1580: Move Actor Objects with a migration Collection](https://codeberg.org/fediverse/fep/src/branch/main/fep/1580/fep-1580.md)
+
 ## References
 
 - Christine Lemmer-Webber, Jessica Tallon, Erin Shepherd, Amy Guy, Evan Prodromou, [ActivityPub], 2018
@@ -118,7 +126,7 @@ After adding the `movedTo` or `copiedTo` property, the actor SHOULD notify its f
 
 [ActivityPub]: https://www.w3.org/TR/activitypub/
 [ActivityVocabulary]: https://www.w3.org/TR/activitystreams-vocabulary/
-[RFC-2119]: https://tools.ietf.org/html/rfc2119.html
+[RFC-2119]: https://datatracker.ietf.org/doc/html/rfc2119.html
 [FEP-c390]: https://codeberg.org/fediverse/fep/src/branch/main/fep/c390/fep-c390.md
 [rel-me]: https://indieweb.org/rel-me