diff --git a/changelog.md b/changelog.md
--- a/changelog.md
+++ b/changelog.md
@@ -1,3 +1,8 @@
+1.0.3
+-----
+
+- Mark all modules `Trustworthy`. (deprecated modules are `Safe` for GHC-7.4+).
+
 1.0.2.2
 -------
 
diff --git a/integer-logarithms.cabal b/integer-logarithms.cabal
--- a/integer-logarithms.cabal
+++ b/integer-logarithms.cabal
@@ -1,5 +1,5 @@
 name:               integer-logarithms
-version:            1.0.2.2
+version:            1.0.3
 cabal-version:      >= 1.10
 author:             Daniel Fischer
 copyright:          (c) 2011 Daniel Fischer
@@ -31,8 +31,9 @@
   GHC==7.10.3,
   GHC==8.0.2,
   GHC==8.2.2,
-  GHC==8.4.3,
-  GHC==8.6.1
+  GHC==8.4.4,
+  GHC==8.6.4,
+  GHC==8.8.1
 
 extra-source-files  : readme.md changelog.md
 
@@ -53,11 +54,10 @@
     base >= 4.3 && < 4.13,
     array >= 0.3 && < 0.6,
     ghc-prim < 0.6
-  if impl(ghc >= 7.10)
-    cpp-options: -DBase48
-  else
-    build-depends: nats >= 1.1 && <1.2
 
+  if !impl(ghc >= 7.10)
+    build-depends: nats >= 1.1.2 && <1.2
+
   if flag(integer-gmp)
     build-depends:
       integer-gmp < 1.1
@@ -98,11 +98,11 @@
   build-depends:
     base,
     integer-logarithms,
-    tasty >= 0.10 && < 1.2,
+    tasty >= 0.10 && < 1.3,
     tasty-smallcheck >= 0.8 && < 0.9,
     tasty-quickcheck >= 0.8 && < 0.11,
     tasty-hunit >= 0.9 && < 0.11,
-    QuickCheck >= 2.10 && < 2.12,
+    QuickCheck >= 2.10 && < 2.14,
     smallcheck >= 1.1.3 && < 1.2
   if !impl(ghc >= 7.10)
     build-depends: nats >= 1.1 && <1.2
diff --git a/src/GHC/Integer/Logarithms/Compat.hs b/src/GHC/Integer/Logarithms/Compat.hs
--- a/src/GHC/Integer/Logarithms/Compat.hs
+++ b/src/GHC/Integer/Logarithms/Compat.hs
@@ -8,6 +8,9 @@
 --
 -- Low level stuff for integer logarithms.
 {-# LANGUAGE CPP, MagicHash, UnboxedTuples #-}
+#if __GLASGOW_HASKELL__ >= 702
+{-# LANGUAGE Trustworthy #-}
+#endif
 module GHC.Integer.Logarithms.Compat
     ( -- * Functions
       integerLogBase#
diff --git a/src/Math/NumberTheory/Logarithms.hs b/src/Math/NumberTheory/Logarithms.hs
--- a/src/Math/NumberTheory/Logarithms.hs
+++ b/src/Math/NumberTheory/Logarithms.hs
@@ -11,6 +11,9 @@
 --
 {-# LANGUAGE CPP #-}
 {-# LANGUAGE MagicHash #-}
+#if __GLASGOW_HASKELL__ >= 702
+{-# LANGUAGE Trustworthy #-}
+#endif
 module Math.NumberTheory.Logarithms
     ( -- * Integer logarithms with input checks
       integerLogBase
@@ -42,7 +45,7 @@
 import Numeric.Natural
 
 import GHC.Integer.Logarithms.Compat
-#if Base48 && defined(MIN_VERSION_integer_gmp)
+#if MIN_VERSION_base(4,8,0) && defined(MIN_VERSION_integer_gmp)
 import GHC.Integer.GMP.Internals (Integer (..))
 import GHC.Natural
 #endif
@@ -313,7 +316,7 @@
 fromNatural = fromIntegral
 
 naturalLog2# :: Natural -> Int#
-#if Base48 && defined(MIN_VERSION_integer_gmp)
+#if MIN_VERSION_base(4,8,0) && defined(MIN_VERSION_integer_gmp)
 naturalLog2# (NatS# b) = wordLog2# b
 naturalLog2# (NatJ# n) = integerLog2# (Jp# n)
 #else
diff --git a/src/Math/NumberTheory/Powers/Integer.hs b/src/Math/NumberTheory/Powers/Integer.hs
--- a/src/Math/NumberTheory/Powers/Integer.hs
+++ b/src/Math/NumberTheory/Powers/Integer.hs
@@ -10,6 +10,13 @@
 -- or 'Word' exponent.
 --
 {-# LANGUAGE CPP          #-}
+#if __GLASGOW_HASKELL__ >= 702
+#if __GLASGOW_HASKELL__ >= 704
+{-# LANGUAGE Safe #-}
+#else
+{-# LANGUAGE Trustworthy #-}
+#endif
+#endif
 module Math.NumberTheory.Powers.Integer
     {-# DEPRECATED "It is no faster than (^)" #-}
     ( integerPower
diff --git a/src/Math/NumberTheory/Powers/Natural.hs b/src/Math/NumberTheory/Powers/Natural.hs
--- a/src/Math/NumberTheory/Powers/Natural.hs
+++ b/src/Math/NumberTheory/Powers/Natural.hs
@@ -10,6 +10,13 @@
 -- or 'Word' exponent.
 --
 {-# LANGUAGE CPP          #-}
+#if __GLASGOW_HASKELL__ >= 702
+#if __GLASGOW_HASKELL__ >= 704
+{-# LANGUAGE Safe #-}
+#else
+{-# LANGUAGE Trustworthy #-}
+#endif
+#endif
 module Math.NumberTheory.Powers.Natural
     {-# DEPRECATED "It is no faster than (^)" #-}
     ( naturalPower