diff --git a/ChangeLog b/ChangeLog
index 869c540..f118e8b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -4,6 +4,8 @@ UNRELEASED Version 0.9.2
       fields with an authserv-id that matches srv_id will be considered for
       ARC signing)
     - Fix cv=none processing for initial signature in chain
+    - Add additional text documenting use of srv_id for ARC signing
+      (LP: #1808301)
     - Refactor canonicalization.py strip_trailing_lines to avoid using re for
       more consistent processing across python versions (Thanks to Jonathan
       Bastien-Filiatrault for the change)
diff --git a/dkim/__init__.py b/dkim/__init__.py
index cab5297..e08edcd 100644
--- a/dkim/__init__.py
+++ b/dkim/__init__.py
@@ -1284,7 +1284,7 @@ def arc_sign(message, selector, domain, privkey,
     @param selector: the DKIM selector value for the signature
     @param domain: the DKIM domain value for the signature
     @param privkey: a PKCS#1 private key in base64-encoded text form
-    @param srv_id: the authserv_id used to identify the ADMD's AR headers
+    @param srv_id: the authserv_id used to identify the ADMD's AR headers and to use for ARC authserv_id
     @param signature_algorithm: the signing algorithm to use when signing
     @param include_headers: a list of strings indicating which headers are to be signed (default all headers not listed as SHOULD NOT sign)
     @param timestamp: the time in integer seconds when the message is sealed (default is int(time.time) based on platform, can be string or int)