Merge pull request #370 from cusma/arc89

Author: SilentRhetoric

ARCs/arc-0089.md

@@ -178,7 +178,7 @@ The Reversible Flags (`byte`) are defined as follows:
 |:-----:|:-------------------------------------------|:-------:|:---------|
 | `LSB` | [ARC-20](./arc-0020.md) Smart ASA          | `False` | Any      |
 |  `1`  | [ARC-62](./arc-0062.md) Circulating Supply | `False` | Any      |
-|  `2`  | Custom, should be reserved for future ARCs | `False` | Any      |
+|  `2`  | Native Token Transfers (NTT) supported     | `False` | Any      |
 |  `3`  | Custom, should be reserved for future ARCs | `False` | Any      |
 |  `4`  | Custom, should be reserved for future ARCs | `False` | Any      |
 |  `5`  | Custom, should be reserved for future ARCs | `False` | Any      |
@@ -210,6 +210,9 @@ If the [ARC-62](./arc-0062.md) support is _enabled_:
 conforming to the [ARC-62](./arc-0062.md#circulating-supply-application-discovery)
 specification.
 
+An ASA **MAY** declare to support <a href="https://wormhole.com/docs/products/token-transfers/native-token-transfers/overview/">Native Token Transfers (NTT)</a>
+on creation or after, setting the `2` bit in the Reversible Flags to `True`.
+
 ###### Irreversible Flags
 
 The Irreversible Flags (`byte`) are defined as follows:
@@ -682,12 +685,15 @@ The decision to migrate existing ASA Metadata to a new version **MUST** be made
 by the ASA Manager Address, by declaring the new Application ID in the Deprecated
 By field of the Metadata Header.
 
-If the Deprecated By field is not `0`, clients **SHALL** point to the new [ARC-90](./arc-0090.md)
-Asset Metadata URI:
+If the Deprecated By field is not `0`:
+
+- The ASA Manager **SHOULD** leave the [Metadata](#metadata) (body) **empty** (i.e., `metadata_size = 0`),
 
-`algorand://<netauth>/app/<deprecated_by_app_id>?box=<base64url_encoded_asset_id>#arc<A>+<B>+<C>...`
+- Clients **SHALL** point to the new [ARC-90](./arc-0090.md) Asset Metadata URI:
 
-and complete it as specified in the [Asset Metadata URI section](#asset-metadata-uri).
+   `algorand://<netauth>/app/<deprecated_by_app_id>?box=<base64url_encoded_asset_id>#arc<A>+<B>+<C>...`
+   
+   and complete it as specified in the [Asset Metadata URI section](#asset-metadata-uri).
 
 ## Rationale
 
@@ -785,9 +791,8 @@ to the existing URIs requiring external infrastructures (e.g., Indexer, IPFS, et
 Since the Asset URL (`au`) field is immutable, the Asset Metadata cannot be discovered
 though an ASA look-up.
 
-Existing ASA willing to migrate metadata to the ASA Metadata Registry **MUST** publish
-the [Asset Metadata URI](#asset-metadata-uri) as [ARC-2](./arc-0002.md) `AssetConfig`
-transaction note field, as follows:
+Existing ASAs willing to backport metadata to the ASA Metadata Registry **MUST**
+publish the [Asset Metadata URI](#asset-metadata-uri) as [ARC-2](./arc-0002.md) message, as follows:
 
 - The `<arc-number>` **MUST** be equal to `89`;
 - The **RECOMMENDED** `<data-format>` are <a href="https://msgpack.org/">MsgPack</a>
@@ -798,13 +803,16 @@ transaction note field, as follows:
 > etc.) it is necessary to **include all the existing role addresses** in the `AssetConfig`.
 > Not doing so would irreversibly disable the RBAC roles!
 
-Clients acquire the migrated [Asset Metadata URI](#asset-metadata-uri) of existing
-ASA inspecting its `AssetConfig` transaction history.
+Clients discover the backport [ARC-2](./arc-0002.md) message inspecting the ASA
+`AssetConfig` transaction history.
+
+Clients **SHOULD** optimistically check ASA metadata existence on the ASA Metadata
+Registry first, to avoid inspecting the transaction history.
 
-### Example - JSON without a version
+### Backporting Message Example - JSON without a version
 
-> The [ARC-2](./arc-0002.md) note to migrate existing [ARC-3](./arc-0003.md) ASA
-> `12345` metadata to the ASA Metadata Registry would be:
+> The [ARC-2](./arc-0002.md) message to backport existing [ARC-3](./arc-0003.md)
+> ASA `12345` metadata to the ASA Metadata Registry would be:
 >
 > ```text
 > arc89:j{"uri": "algorand://<netauth>/app/<singleton_arc89_app_id>?box=AAAAAAAAMDk#arc3"}