diff --git a/liquid-base.cabal b/liquid-base.cabal
--- a/liquid-base.cabal
+++ b/liquid-base.cabal
@@ -1,6 +1,6 @@
-cabal-version:      1.24
+cabal-version:      2.0
 name:               liquid-base
-version:            4.15.0.0
+version:            4.15.1.0
 synopsis:           Drop-in base replacement for LiquidHaskell
 description:        Drop-in base replacement for LiquidHaskell.
 license:            BSD3
@@ -23,7 +23,7 @@
                     src/Control/*.spec
 
 custom-setup
-  setup-depends: Cabal, base, liquidhaskell
+  setup-depends: Cabal<4, base<5, liquidhaskell
 
 library
   exposed-modules:  Control.Applicative
@@ -244,13 +244,12 @@
                     Liquid.Prelude.Totality
 
   hs-source-dirs:     src
-  build-depends:      base                 == 4.15.0.0
+  build-depends:
+                      base                 ^>= 4.15.1.0
                     , liquid-ghc-prim
-                    , liquidhaskell        >= 0.8.10.1
-  if impl(ghc < 9)
-    build-depends:    integer-gmp < 1.0.4.0
+                    , liquidhaskell        >= 0.9.0.2
   default-language:   Haskell2010
   default-extensions: PackageImports
                       NoImplicitPrelude
   if impl(ghc >= 8.10)
-    ghc-options: -fplugin=LiquidHaskell
+    ghc-options: -fplugin=LiquidHaskell -fplugin-opt=LiquidHaskell:--no-positivity-check
diff --git a/src/Data/Typeable.hs b/src/Data/Typeable.hs
--- a/src/Data/Typeable.hs
+++ b/src/Data/Typeable.hs
diff --git a/src/Foreign/ForeignPtr.spec b/src/Foreign/ForeignPtr.spec
--- a/src/Foreign/ForeignPtr.spec
+++ b/src/Foreign/ForeignPtr.spec
@@ -3,7 +3,7 @@
 import GHC.ForeignPtr
 import Foreign.Ptr
 
-GHC.ForeignPtr.withForeignPtr :: forall a b. fp:(GHC.ForeignPtr.ForeignPtr a) 
+GHC.ForeignPtr.withForeignPtr :: forall a b. fp:(GHC.ForeignPtr.ForeignPtr a)
   -> ((PtrN a (fplen fp)) -> GHC.Types.IO b) 
   -> (GHC.Types.IO b)
 
diff --git a/src/GHC/Maybe.spec b/src/GHC/Maybe.spec
new file mode 100644
--- /dev/null
+++ b/src/GHC/Maybe.spec
@@ -0,0 +1,3 @@
+module spec GHC.Maybe where
+
+data Maybe a = Nothing | Just a
diff --git a/src/Prelude.hs b/src/Prelude.hs
--- a/src/Prelude.hs
+++ b/src/Prelude.hs
@@ -9,6 +9,7 @@
 import GHC.Exts
 import GHC.Int
 import GHC.List
+import GHC.Maybe
 import GHC.Num
 import GHC.Real
 import GHC.Types
diff --git a/src/Prelude.spec b/src/Prelude.spec
--- a/src/Prelude.spec
+++ b/src/Prelude.spec
@@ -3,6 +3,7 @@
 import GHC.Base
 import GHC.Int
 import GHC.List
+import GHC.Maybe
 import GHC.Num
 import GHC.Real
 import GHC.Word