diff --git a/CHANGELOG b/CHANGELOG
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,5 @@
+0.4.0.3 (2025-02-11):
+    - Updating version bounds for GHC 9.12
 0.4.0.2 (2024-08-28):
     - Updating version bounds for GHC 9.10
 0.4.0.1 (2024-02-19):
diff --git a/unix-bytestring.cabal b/unix-bytestring.cabal
--- a/unix-bytestring.cabal
+++ b/unix-bytestring.cabal
@@ -6,18 +6,18 @@
 --    <https://github.com/haskell/cabal/issues/4899>
 
 ----------------------------------------------------------------
--- wren gayle romano <wren@cpan.org>                ~ 2024-08-28
+-- wren gayle romano <wren@cpan.org>                ~ 2025-02-11
 ----------------------------------------------------------------
 
 Name:           unix-bytestring
-Version:        0.4.0.2
+Version:        0.4.0.3
 Build-Type:     Simple
 Stability:      provisional
 Homepage:       https://wrengr.org/software/hackage.html
 Bug-Reports:    https://github.com/wrengr/unix-bytestring/issues
 Author:         wren gayle romano
 Maintainer:     wren@cpan.org
-Copyright:      2010–2024 wren romano
+Copyright:      2010–2025 wren romano
 -- Cabal-2.2 requires us to say "BSD-3-Clause" not "BSD3"
 License:        BSD-3-Clause
 License-File:   LICENSE
@@ -54,7 +54,8 @@
     GHC ==9.4.8,
     GHC ==9.6.5,
     GHC ==9.8.2,
-    GHC ==9.10.1
+    GHC ==9.10.1,
+    GHC ==9.12.1
 
 Source-Repository head
     Type:     git
@@ -76,10 +77,8 @@
     -- them on our own for better backwards compatibility.
     --
     -- FIXME: unix-2.8.0.0 introduces some additional conflicts
-    --
-    -- Not sure what the real minbound is on bytestring...
-    Build-Depends: base       >= 4.1     && < 4.21
-                 , bytestring >= 0.9.1.5 && < 0.13
+    Build-Depends: base       >= 4.9    && < 4.22
+                 , bytestring >= 0.10.8 && < 0.13
 
 ----------------------------------------------------------------
 ----------------------------------------------------------- fin.