Update changelog for DAP-12.

Also, bump the version tag.

draft-ietf-ppm-dap.md

@@ -152,6 +152,11 @@ input is ever seen in the clear by any aggregator.
 
 12:
 
+- Add support for "asynchronous" aggregation, based on the Leader polling the
+  Helper for collection. (\*)
+
+- Clarify the requirements around report replay protection.
+
 - Remove the `max_batch_size` parameter of the fixed-size query type.
 
 - Rename the "fixed-size" query type to "leader-selected", to align the name
@@ -164,6 +169,14 @@ input is ever seen in the clear by any aggregator.
   was removed in draft 11, as it is required to decrypt collection results in
   some cases. (\*)
 
+- Document distributed-system and synchronization concerns in the operational
+  considerations section.
+
+- Document additional storage and runtime requirements in the operational
+  considerations section.
+
+- Bump version tag from "dap-11" to "dap-12". (\*)
+
 11:
 
 - Remove support for multi-collection of batches, as well as the fixed-size
@@ -1158,7 +1171,7 @@ follows:
 
 ~~~ pseudocode
 enc, payload = SealBase(pk,
-  "dap-11 input share" || 0x01 || server_role,
+  "dap-12 input share" || 0x01 || server_role,
   input_share_aad, plaintext_input_share)
 ~~~
 
@@ -1780,7 +1793,7 @@ attempts decryption of the payload with the following procedure:
 
 ~~~ pseudocode
 plaintext_input_share = OpenBase(encrypted_input_share.enc, sk,
-  "dap-11 input share" || 0x01 || server_role,
+  "dap-12 input share" || 0x01 || server_role,
   input_share_aad, encrypted_input_share.payload)
 ~~~
 
@@ -2388,7 +2401,7 @@ done as follows:
 ~~~ pseudocode
 (enc, payload) = SealBase(
     pk,
-    "dap-11 aggregate share" || server_role || 0x00,
+    "dap-12 aggregate share" || server_role || 0x00,
     agg_share_aad,
     agg_share)
 ~~~
@@ -2422,7 +2435,7 @@ batch selector, decryption works as follows:
 agg_share = OpenBase(
     enc_share.enc,
     sk,
-    "dap-11 aggregate share" || server_role || 0x00,
+    "dap-12 aggregate share" || server_role || 0x00,
     agg_share_aad,
     enc_share.payload)
 ~~~