diff --git a/CHANGELOG.md b/CHANGELOG.md
index b05296b2f4..3c3aaa8883 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,10 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
  - #2887, Add Preference `max-affected` to limit affected resources - @taimoorzaeem
 
+### Deprecated
+
+ - `Prefer: params=single-object` is deprecated. Use [a function with a single unnamed JSON parameter](https://postgrest.org/en/latest/references/api/stored_procedures.html#s-proc-single-json) instead. - @steve-chavez
+
 ## [12.0.2] - 2023-12-20
 
 ### Fixed
diff --git a/src/PostgREST/ApiRequest/Preferences.hs b/src/PostgREST/ApiRequest/Preferences.hs
index 1b87746239..3bc6c50a24 100644
--- a/src/PostgREST/ApiRequest/Preferences.hs
+++ b/src/PostgREST/ApiRequest/Preferences.hs
@@ -232,6 +232,7 @@ instance ToHeaderValue PreferRepresentation where
   toHeaderValue HeadersOnly = "return=headers-only"
 
 -- | How to pass parameters to stored procedures.
+-- TODO: deprecated. Remove on next major version.
 data PreferParameters
   = SingleObject    -- ^ Pass all parameters as a single json object to a stored procedure.
   deriving Eq