diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,8 @@
 # Changelog for ghc-lib-parser-ex
 
+## 9.0.0.1 released 2021-02-05
+- Upgrade Cabal defaults flag to 9.0.1
+
 ## 9.0.0.0 released 2021-02-05
 - Update to ghc-9.0.1
 
diff --git a/ghc-lib-parser-ex.cabal b/ghc-lib-parser-ex.cabal
--- a/ghc-lib-parser-ex.cabal
+++ b/ghc-lib-parser-ex.cabal
@@ -1,6 +1,6 @@
 cabal-version: >= 1.18
 name:           ghc-lib-parser-ex
-version:        9.0.0.0
+version:        9.0.0.1
 description:    Please see the README on GitHub at <https://github.com/shayne-fletcher/ghc-lib-parser-ex#readme>
 homepage:       https://github.com/shayne-fletcher/ghc-lib-parser-ex#readme
 bug-reports:    https://github.com/shayne-fletcher/ghc-lib-parser-ex/issues
@@ -63,15 +63,15 @@
       uniplate >= 1.5,
       bytestring >= 0.10.8.2,
       containers >= 0.5.8.1
-  if flag(auto) && impl(ghc >= 8.10.0) && impl(ghc < 8.11.0)
+  if flag(auto) && impl(ghc >= 9.0.0) && impl(ghc < 9.0.1)
     build-depends:
-      ghc == 8.10.*,
+      ghc == 9.0.*,
       ghc-boot-th,
       ghc-boot
   else
     if flag(auto)
       build-depends:
-        ghc-lib-parser == 8.10.*
+        ghc-lib-parser == 9.0.*
     else
       if flag(no-ghc-lib)
         build-depends: