diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,13 @@
 
 ## Unreleased
 
+## 0.1.2.1 - 2026-07-20
+
+### Changed
+
+- Upgraded the `baikai` dependency to the `0.4` series (`>=0.4 && <0.5`).
+  Dependency bounds only — no changes to the exported API.
+
 ## 0.1.2.0 - 2026-07-05
 
 ### Added
diff --git a/shikumi-cache.cabal b/shikumi-cache.cabal
--- a/shikumi-cache.cabal
+++ b/shikumi-cache.cabal
@@ -1,6 +1,6 @@
 cabal-version:   3.4
 name:            shikumi-cache
-version:         0.1.2.0
+version:         0.1.2.1
 synopsis:        Content-addressed response caching for shikumi (EP-6)
 category:        AI
 description:
@@ -45,7 +45,7 @@
 
   build-depends:
     , aeson
-    , baikai         >=0.3      && <0.4
+    , baikai         >=0.4      && <0.5
     , base           >=4.20     && <5
     , blake3
     , bytestring
@@ -69,7 +69,7 @@
   ghc-options:    -threaded -with-rtsopts=-N
   build-depends:
     , aeson
-    , baikai         >=0.3      && <0.4
+    , baikai         >=0.4      && <0.5
     , base
     , bytestring
     , containers