diff --git a/changelog.md b/changelog.md
--- a/changelog.md
+++ b/changelog.md
@@ -1,5 +1,10 @@
 # Change Log
 
+## [1.11.1]
+- all modules Safe or Trustworthy
+- fix NFData instances for DiffTime, NominalDiffTime, TimeOfDay
+- add missing Ix, Enum, NFData instances to DayOfWeek, CalendarDiffDays, CalendarDiffTime, Month, Quarter, QuarterOfYear
+
 ## [1.11]
 - new calendrical type synonyms and abstract constructors
 - new Month type, with appropriate functions
diff --git a/configure.ac b/configure.ac
--- a/configure.ac
+++ b/configure.ac
@@ -1,4 +1,4 @@
-AC_INIT([Haskell time package], [1.11], [ashley@semantic.org], [time])
+AC_INIT([Haskell time package], [1.11.1], [ashley@semantic.org], [time])
 
 # Safety check: Ensure that we are in the correct source directory.
 AC_CONFIG_SRCDIR([lib/include/HsTime.h])
diff --git a/lib/Data/Format.hs b/lib/Data/Format.hs
--- a/lib/Data/Format.hs
+++ b/lib/Data/Format.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 module Data.Format
     ( Productish(..)
     , Summish(..)
diff --git a/lib/Data/Time.hs b/lib/Data/Time.hs
--- a/lib/Data/Time.hs
+++ b/lib/Data/Time.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 {-|
 
 = Quick Start
diff --git a/lib/Data/Time/Calendar.hs b/lib/Data/Time/Calendar.hs
--- a/lib/Data/Time/Calendar.hs
+++ b/lib/Data/Time/Calendar.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 module Data.Time.Calendar
     ( module Data.Time.Calendar.Days
     , module Data.Time.Calendar.CalendarDiffDays
diff --git a/lib/Data/Time/Calendar/CalendarDiffDays.hs b/lib/Data/Time/Calendar/CalendarDiffDays.hs
--- a/lib/Data/Time/Calendar/CalendarDiffDays.hs
+++ b/lib/Data/Time/Calendar/CalendarDiffDays.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 module Data.Time.Calendar.CalendarDiffDays
     (
         -- * Calendar Duration
@@ -10,6 +12,7 @@
 #endif
 import Data.Typeable
 import Data.Data
+import Control.DeepSeq
 
 data CalendarDiffDays = CalendarDiffDays
     { cdMonths :: Integer
@@ -24,6 +27,9 @@
     -- ^ @since 1.9.2
 #endif
     )
+
+instance NFData CalendarDiffDays where
+    rnf (CalendarDiffDays m d) = rnf m `seq` rnf d `seq` ()
 
 -- | Additive
 instance Semigroup CalendarDiffDays where
diff --git a/lib/Data/Time/Calendar/Days.hs b/lib/Data/Time/Calendar/Days.hs
--- a/lib/Data/Time/Calendar/Days.hs
+++ b/lib/Data/Time/Calendar/Days.hs
@@ -1,5 +1,4 @@
-{-# LANGUAGE Trustworthy #-}
-{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE Safe #-}
 
 module Data.Time.Calendar.Days
     (
@@ -21,7 +20,6 @@
 instance NFData Day where
     rnf (ModifiedJulianDay a) = rnf a
 
--- necessary because H98 doesn't have "cunning newtype" derivation
 instance Enum Day where
     succ (ModifiedJulianDay a) = ModifiedJulianDay (succ a)
     pred (ModifiedJulianDay a) = ModifiedJulianDay (pred a)
@@ -33,7 +31,6 @@
     enumFromThenTo (ModifiedJulianDay a) (ModifiedJulianDay b) (ModifiedJulianDay c) =
         fmap ModifiedJulianDay (enumFromThenTo a b c)
 
--- necessary because H98 doesn't have "cunning newtype" derivation
 instance Ix Day where
     range (ModifiedJulianDay a, ModifiedJulianDay b) = fmap ModifiedJulianDay (range (a, b))
     index (ModifiedJulianDay a, ModifiedJulianDay b) (ModifiedJulianDay c) = index (a, b) c
diff --git a/lib/Data/Time/Calendar/Easter.hs b/lib/Data/Time/Calendar/Easter.hs
--- a/lib/Data/Time/Calendar/Easter.hs
+++ b/lib/Data/Time/Calendar/Easter.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 module Data.Time.Calendar.Easter
     ( sundayAfter
     , orthodoxPaschalMoon
diff --git a/lib/Data/Time/Calendar/Gregorian.hs b/lib/Data/Time/Calendar/Gregorian.hs
--- a/lib/Data/Time/Calendar/Gregorian.hs
+++ b/lib/Data/Time/Calendar/Gregorian.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE Safe #-}
 {-# OPTIONS -fno-warn-orphans #-}
 
 module Data.Time.Calendar.Gregorian
diff --git a/lib/Data/Time/Calendar/Julian.hs b/lib/Data/Time/Calendar/Julian.hs
--- a/lib/Data/Time/Calendar/Julian.hs
+++ b/lib/Data/Time/Calendar/Julian.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 module Data.Time.Calendar.Julian
     ( Year
     , MonthOfYear
diff --git a/lib/Data/Time/Calendar/JulianYearDay.hs b/lib/Data/Time/Calendar/JulianYearDay.hs
--- a/lib/Data/Time/Calendar/JulianYearDay.hs
+++ b/lib/Data/Time/Calendar/JulianYearDay.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 module Data.Time.Calendar.JulianYearDay
     (
     -- * Year and day format
diff --git a/lib/Data/Time/Calendar/Month.hs b/lib/Data/Time/Calendar/Month.hs
--- a/lib/Data/Time/Calendar/Month.hs
+++ b/lib/Data/Time/Calendar/Month.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE Safe #-}
 #if __GLASGOW_HASKELL__ < 802
 {-# OPTIONS_GHC -Wno-incomplete-patterns -Wno-incomplete-uni-patterns #-}
 #endif
@@ -21,10 +21,32 @@
 import Data.Fixed
 import Text.Read
 import Text.ParserCombinators.ReadP
+import Control.DeepSeq
+import Data.Ix
 
 -- | An absolute count of common calendar months.
 -- Number is equal to @(year * 12) + (monthOfYear - 1)@.
 newtype Month = MkMonth Integer deriving (Eq, Ord, Data, Typeable)
+
+instance NFData Month where
+    rnf (MkMonth m) = rnf m
+
+instance Enum Month where
+    succ (MkMonth a) = MkMonth (succ a)
+    pred (MkMonth a) = MkMonth (pred a)
+    toEnum = MkMonth . toEnum
+    fromEnum (MkMonth a) = fromEnum a
+    enumFrom (MkMonth a) = fmap MkMonth (enumFrom a)
+    enumFromThen (MkMonth a) (MkMonth b) = fmap MkMonth (enumFromThen a b)
+    enumFromTo (MkMonth a) (MkMonth b) = fmap MkMonth (enumFromTo a b)
+    enumFromThenTo (MkMonth a) (MkMonth b) (MkMonth c) =
+        fmap MkMonth (enumFromThenTo a b c)
+
+instance Ix Month where
+    range (MkMonth a, MkMonth b) = fmap MkMonth (range (a, b))
+    index (MkMonth a, MkMonth b) (MkMonth c) = index (a, b) c
+    inRange (MkMonth a, MkMonth b) (MkMonth c) = inRange (a, b) c
+    rangeSize (MkMonth a, MkMonth b) = rangeSize (a, b)
 
 -- | Show as @yyyy-mm@.
 instance Show Month where
diff --git a/lib/Data/Time/Calendar/MonthDay.hs b/lib/Data/Time/Calendar/MonthDay.hs
--- a/lib/Data/Time/Calendar/MonthDay.hs
+++ b/lib/Data/Time/Calendar/MonthDay.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 module Data.Time.Calendar.MonthDay
     ( MonthOfYear, DayOfMonth, DayOfYear
     , monthAndDayToDayOfYear
diff --git a/lib/Data/Time/Calendar/OrdinalDate.hs b/lib/Data/Time/Calendar/OrdinalDate.hs
--- a/lib/Data/Time/Calendar/OrdinalDate.hs
+++ b/lib/Data/Time/Calendar/OrdinalDate.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 -- | ISO 8601 Ordinal Date format
 module Data.Time.Calendar.OrdinalDate (Day, Year, DayOfYear, WeekOfYear, module Data.Time.Calendar.OrdinalDate) where
 
diff --git a/lib/Data/Time/Calendar/Private.hs b/lib/Data/Time/Calendar/Private.hs
--- a/lib/Data/Time/Calendar/Private.hs
+++ b/lib/Data/Time/Calendar/Private.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 module Data.Time.Calendar.Private where
 
 import Data.Fixed
diff --git a/lib/Data/Time/Calendar/Quarter.hs b/lib/Data/Time/Calendar/Quarter.hs
--- a/lib/Data/Time/Calendar/Quarter.hs
+++ b/lib/Data/Time/Calendar/Quarter.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE Safe #-}
 #if __GLASGOW_HASKELL__ < 802
 {-# OPTIONS_GHC -Wno-incomplete-patterns -Wno-incomplete-uni-patterns #-}
 #endif
@@ -22,9 +22,11 @@
 import Data.Fixed
 import Text.Read
 import Text.ParserCombinators.ReadP
+import Control.DeepSeq
+import Data.Ix
 
 -- | Quarters of each year. Each quarter corresponds to three months.
-data QuarterOfYear = Q1 | Q2 | Q3 | Q4 deriving (Eq, Ord, Data, Typeable, Read, Show)
+data QuarterOfYear = Q1 | Q2 | Q3 | Q4 deriving (Eq, Ord, Data, Typeable, Read, Show, Ix)
 
 -- | maps Q1..Q4 to 1..4
 instance Enum QuarterOfYear where
@@ -43,9 +45,35 @@
     minBound = Q1
     maxBound = Q4
 
+instance NFData QuarterOfYear where
+    rnf Q1 = ()
+    rnf Q2 = ()
+    rnf Q3 = ()
+    rnf Q4 = ()
+
 -- | An absolute count of year quarters.
 -- Number is equal to @(year * 4) + (quarterOfYear - 1)@.
 newtype Quarter = MkQuarter Integer deriving (Eq, Ord, Data, Typeable)
+
+instance NFData Quarter where
+    rnf (MkQuarter m) = rnf m
+
+instance Enum Quarter where
+    succ (MkQuarter a) = MkQuarter (succ a)
+    pred (MkQuarter a) = MkQuarter (pred a)
+    toEnum = MkQuarter . toEnum
+    fromEnum (MkQuarter a) = fromEnum a
+    enumFrom (MkQuarter a) = fmap MkQuarter (enumFrom a)
+    enumFromThen (MkQuarter a) (MkQuarter b) = fmap MkQuarter (enumFromThen a b)
+    enumFromTo (MkQuarter a) (MkQuarter b) = fmap MkQuarter (enumFromTo a b)
+    enumFromThenTo (MkQuarter a) (MkQuarter b) (MkQuarter c) =
+        fmap MkQuarter (enumFromThenTo a b c)
+
+instance Ix Quarter where
+    range (MkQuarter a, MkQuarter b) = fmap MkQuarter (range (a, b))
+    index (MkQuarter a, MkQuarter b) (MkQuarter c) = index (a, b) c
+    inRange (MkQuarter a, MkQuarter b) (MkQuarter c) = inRange (a, b) c
+    rangeSize (MkQuarter a, MkQuarter b) = rangeSize (a, b)
 
 -- | Show as @yyyy-Qn@.
 instance Show Quarter where
diff --git a/lib/Data/Time/Calendar/Types.hs b/lib/Data/Time/Calendar/Types.hs
--- a/lib/Data/Time/Calendar/Types.hs
+++ b/lib/Data/Time/Calendar/Types.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 module Data.Time.Calendar.Types where
 
 
diff --git a/lib/Data/Time/Calendar/Week.hs b/lib/Data/Time/Calendar/Week.hs
--- a/lib/Data/Time/Calendar/Week.hs
+++ b/lib/Data/Time/Calendar/Week.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 module Data.Time.Calendar.Week
     (
       -- * Week
@@ -8,7 +10,9 @@
     ) where
 
 import Data.Fixed
+import Data.Ix
 import Data.Data
+import Control.DeepSeq
 import Data.Time.Calendar.Days
 
 data DayOfWeek
@@ -19,7 +23,16 @@
     | Friday
     | Saturday
     | Sunday
-    deriving (Eq, Show, Read, Data, Typeable, Ord)
+    deriving (Eq, Show, Read, Data, Typeable, Ord, Ix)
+
+instance NFData DayOfWeek where
+    rnf Monday = ()
+    rnf Tuesday = ()
+    rnf Wednesday = ()
+    rnf Thursday = ()
+    rnf Friday = ()
+    rnf Saturday = ()
+    rnf Sunday = ()
 
 -- | \"Circular\", so for example @[Tuesday ..]@ gives an endless sequence.
 -- Also: 'fromEnum' gives [1 .. 7] for [Monday .. Sunday], and 'toEnum' performs mod 7 to give a cycle of days.
diff --git a/lib/Data/Time/Calendar/WeekDate.hs b/lib/Data/Time/Calendar/WeekDate.hs
--- a/lib/Data/Time/Calendar/WeekDate.hs
+++ b/lib/Data/Time/Calendar/WeekDate.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 -- | Week-based calendars
 module Data.Time.Calendar.WeekDate
     (
diff --git a/lib/Data/Time/Clock.hs b/lib/Data/Time/Clock.hs
--- a/lib/Data/Time/Clock.hs
+++ b/lib/Data/Time/Clock.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 -- | Types and functions for UTC and UT1
 module Data.Time.Clock
     ( module Data.Time.Clock.Internal.UniversalTime
diff --git a/lib/Data/Time/Clock/Internal/AbsoluteTime.hs b/lib/Data/Time/Clock/Internal/AbsoluteTime.hs
--- a/lib/Data/Time/Clock/Internal/AbsoluteTime.hs
+++ b/lib/Data/Time/Clock/Internal/AbsoluteTime.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 -- | TAI and leap-second maps for converting to UTC: most people won't need this module.
 module Data.Time.Clock.Internal.AbsoluteTime
     (
diff --git a/lib/Data/Time/Clock/Internal/CTimeval.hs b/lib/Data/Time/Clock/Internal/CTimeval.hs
--- a/lib/Data/Time/Clock/Internal/CTimeval.hs
+++ b/lib/Data/Time/Clock/Internal/CTimeval.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 module Data.Time.Clock.Internal.CTimeval where
 #ifndef mingw32_HOST_OS
 -- All Unix-specific, this
diff --git a/lib/Data/Time/Clock/Internal/DiffTime.hs b/lib/Data/Time/Clock/Internal/DiffTime.hs
--- a/lib/Data/Time/Clock/Internal/DiffTime.hs
+++ b/lib/Data/Time/Clock/Internal/DiffTime.hs
@@ -25,12 +25,9 @@
     MkDiffTime Pico
     deriving (Eq, Ord, Data, Typeable)
 
--- necessary because H98 doesn't have "cunning newtype" derivation
-instance NFData DiffTime -- FIXME: Data.Fixed had no NFData instances yet at time of writing
-                                                                                             where
-    rnf dt = seq dt ()
+instance NFData DiffTime where
+    rnf (MkDiffTime t) = rnf t
 
--- necessary because H98 doesn't have "cunning newtype" derivation
 instance Enum DiffTime where
     succ (MkDiffTime a) = MkDiffTime (succ a)
     pred (MkDiffTime a) = MkDiffTime (pred a)
@@ -50,7 +47,6 @@
         _ <- lift $ char 's'
         return $ MkDiffTime t
 
--- necessary because H98 doesn't have "cunning newtype" derivation
 instance Num DiffTime where
     (MkDiffTime a) + (MkDiffTime b) = MkDiffTime (a + b)
     (MkDiffTime a) - (MkDiffTime b) = MkDiffTime (a - b)
@@ -60,17 +56,14 @@
     signum (MkDiffTime a) = MkDiffTime (signum a)
     fromInteger i = MkDiffTime (fromInteger i)
 
--- necessary because H98 doesn't have "cunning newtype" derivation
 instance Real DiffTime where
     toRational (MkDiffTime a) = toRational a
 
--- necessary because H98 doesn't have "cunning newtype" derivation
 instance Fractional DiffTime where
     (MkDiffTime a) / (MkDiffTime b) = MkDiffTime (a / b)
     recip (MkDiffTime a) = MkDiffTime (recip a)
     fromRational r = MkDiffTime (fromRational r)
 
--- necessary because H98 doesn't have "cunning newtype" derivation
 instance RealFrac DiffTime where
     properFraction (MkDiffTime a) = let
         (b', a') = properFraction a
diff --git a/lib/Data/Time/Clock/Internal/NominalDiffTime.hs b/lib/Data/Time/Clock/Internal/NominalDiffTime.hs
--- a/lib/Data/Time/Clock/Internal/NominalDiffTime.hs
+++ b/lib/Data/Time/Clock/Internal/NominalDiffTime.hs
@@ -41,10 +41,8 @@
 nominalDiffTimeToSeconds :: NominalDiffTime -> Pico
 nominalDiffTimeToSeconds (MkNominalDiffTime t) = t
 
--- necessary because H98 doesn't have "cunning newtype" derivation
-instance NFData NominalDiffTime -- FIXME: Data.Fixed had no NFData instances yet at time of writing
-                                                                                                    where
-    rnf ndt = seq ndt ()
+instance NFData NominalDiffTime where
+    rnf (MkNominalDiffTime t) = rnf t
 
 instance Enum NominalDiffTime where
     succ (MkNominalDiffTime a) = MkNominalDiffTime (succ a)
@@ -66,7 +64,6 @@
         _ <- lift $ char 's'
         return $ MkNominalDiffTime t
 
--- necessary because H98 doesn't have "cunning newtype" derivation
 instance Num NominalDiffTime where
     (MkNominalDiffTime a) + (MkNominalDiffTime b) = MkNominalDiffTime (a + b)
     (MkNominalDiffTime a) - (MkNominalDiffTime b) = MkNominalDiffTime (a - b)
@@ -76,17 +73,14 @@
     signum (MkNominalDiffTime a) = MkNominalDiffTime (signum a)
     fromInteger i = MkNominalDiffTime (fromInteger i)
 
--- necessary because H98 doesn't have "cunning newtype" derivation
 instance Real NominalDiffTime where
     toRational (MkNominalDiffTime a) = toRational a
 
--- necessary because H98 doesn't have "cunning newtype" derivation
 instance Fractional NominalDiffTime where
     (MkNominalDiffTime a) / (MkNominalDiffTime b) = MkNominalDiffTime (a / b)
     recip (MkNominalDiffTime a) = MkNominalDiffTime (recip a)
     fromRational r = MkNominalDiffTime (fromRational r)
 
--- necessary because H98 doesn't have "cunning newtype" derivation
 instance RealFrac NominalDiffTime where
     properFraction (MkNominalDiffTime a) = (i, MkNominalDiffTime f)
       where
diff --git a/lib/Data/Time/Clock/Internal/POSIXTime.hs b/lib/Data/Time/Clock/Internal/POSIXTime.hs
--- a/lib/Data/Time/Clock/Internal/POSIXTime.hs
+++ b/lib/Data/Time/Clock/Internal/POSIXTime.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 module Data.Time.Clock.Internal.POSIXTime where
 
 import Data.Time.Clock.Internal.NominalDiffTime
diff --git a/lib/Data/Time/Clock/Internal/UTCDiff.hs b/lib/Data/Time/Clock/Internal/UTCDiff.hs
--- a/lib/Data/Time/Clock/Internal/UTCDiff.hs
+++ b/lib/Data/Time/Clock/Internal/UTCDiff.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 module Data.Time.Clock.Internal.UTCDiff where
 
 import Data.Time.Clock.Internal.NominalDiffTime
diff --git a/lib/Data/Time/Clock/Internal/UTCTime.hs b/lib/Data/Time/Clock/Internal/UTCTime.hs
--- a/lib/Data/Time/Clock/Internal/UTCTime.hs
+++ b/lib/Data/Time/Clock/Internal/UTCTime.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 module Data.Time.Clock.Internal.UTCTime
     (
     -- * UTC
diff --git a/lib/Data/Time/Clock/Internal/UniversalTime.hs b/lib/Data/Time/Clock/Internal/UniversalTime.hs
--- a/lib/Data/Time/Clock/Internal/UniversalTime.hs
+++ b/lib/Data/Time/Clock/Internal/UniversalTime.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 module Data.Time.Clock.Internal.UniversalTime
     (
     -- * Universal Time
@@ -14,6 +16,5 @@
     { getModJulianDate :: Rational
     } deriving (Eq, Ord, Data, Typeable)
 
--- necessary because H98 doesn't have "cunning newtype" derivation
 instance NFData UniversalTime where
     rnf (ModJulianDate a) = rnf a
diff --git a/lib/Data/Time/Clock/POSIX.hs b/lib/Data/Time/Clock/POSIX.hs
--- a/lib/Data/Time/Clock/POSIX.hs
+++ b/lib/Data/Time/Clock/POSIX.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 -- | POSIX time, if you need to deal with timestamps and the like.
 -- Most people won't need this module.
 --
diff --git a/lib/Data/Time/Clock/System.hs b/lib/Data/Time/Clock/System.hs
--- a/lib/Data/Time/Clock/System.hs
+++ b/lib/Data/Time/Clock/System.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 -- | Fast access to the system clock.
 module Data.Time.Clock.System
     ( systemEpochDay
diff --git a/lib/Data/Time/Clock/TAI.hs b/lib/Data/Time/Clock/TAI.hs
--- a/lib/Data/Time/Clock/TAI.hs
+++ b/lib/Data/Time/Clock/TAI.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE Safe #-}
 {-# OPTIONS -fno-warn-orphans #-}
 
 -- | TAI and leap-second maps for converting to UTC: most people won't need this module.
diff --git a/lib/Data/Time/Format.hs b/lib/Data/Time/Format.hs
--- a/lib/Data/Time/Format.hs
+++ b/lib/Data/Time/Format.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 module Data.Time.Format
     (
     -- * UNIX-style formatting
diff --git a/lib/Data/Time/Format/Format/Class.hs b/lib/Data/Time/Format/Format/Class.hs
--- a/lib/Data/Time/Format/Format/Class.hs
+++ b/lib/Data/Time/Format/Format/Class.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 module Data.Time.Format.Format.Class
     (
         -- * Formatting
diff --git a/lib/Data/Time/Format/Format/Instances.hs b/lib/Data/Time/Format/Format/Instances.hs
--- a/lib/Data/Time/Format/Format/Instances.hs
+++ b/lib/Data/Time/Format/Format/Instances.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE Safe #-}
 {-# OPTIONS -fno-warn-orphans #-}
 #if __GLASGOW_HASKELL__ < 802
 {-# OPTIONS_GHC -Wno-incomplete-patterns -Wno-incomplete-uni-patterns #-}
diff --git a/lib/Data/Time/Format/ISO8601.hs b/lib/Data/Time/Format/ISO8601.hs
--- a/lib/Data/Time/Format/ISO8601.hs
+++ b/lib/Data/Time/Format/ISO8601.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 module Data.Time.Format.ISO8601
     (
         -- * Format
diff --git a/lib/Data/Time/Format/Internal.hs b/lib/Data/Time/Format/Internal.hs
--- a/lib/Data/Time/Format/Internal.hs
+++ b/lib/Data/Time/Format/Internal.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 {-|
 The contents of this module is liable to change, or disappear entirely.
 Please <https://github.com/haskell/time/issues/new let me know> if you depend on anything here.
diff --git a/lib/Data/Time/Format/Locale.hs b/lib/Data/Time/Format/Locale.hs
--- a/lib/Data/Time/Format/Locale.hs
+++ b/lib/Data/Time/Format/Locale.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 -- Note: this file derives from old-locale:System.Locale.hs, which is copyright (c) The University of Glasgow 2001
 module Data.Time.Format.Locale
     ( TimeLocale(..)
diff --git a/lib/Data/Time/Format/Parse.hs b/lib/Data/Time/Format/Parse.hs
--- a/lib/Data/Time/Format/Parse.hs
+++ b/lib/Data/Time/Format/Parse.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE Safe #-}
 {-# OPTIONS -fno-warn-orphans #-}
 
 module Data.Time.Format.Parse
diff --git a/lib/Data/Time/Format/Parse/Class.hs b/lib/Data/Time/Format/Parse/Class.hs
--- a/lib/Data/Time/Format/Parse/Class.hs
+++ b/lib/Data/Time/Format/Parse/Class.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 module Data.Time.Format.Parse.Class
     (
         -- * Parsing
diff --git a/lib/Data/Time/Format/Parse/Instances.hs b/lib/Data/Time/Format/Parse/Instances.hs
--- a/lib/Data/Time/Format/Parse/Instances.hs
+++ b/lib/Data/Time/Format/Parse/Instances.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE Safe #-}
 {-# OPTIONS -fno-warn-orphans #-}
 
 module Data.Time.Format.Parse.Instances
diff --git a/lib/Data/Time/LocalTime.hs b/lib/Data/Time/LocalTime.hs
--- a/lib/Data/Time/LocalTime.hs
+++ b/lib/Data/Time/LocalTime.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 module Data.Time.LocalTime
     (
     -- * Time zones
diff --git a/lib/Data/Time/LocalTime/Internal/CalendarDiffTime.hs b/lib/Data/Time/LocalTime/Internal/CalendarDiffTime.hs
--- a/lib/Data/Time/LocalTime/Internal/CalendarDiffTime.hs
+++ b/lib/Data/Time/LocalTime/Internal/CalendarDiffTime.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 module Data.Time.LocalTime.Internal.CalendarDiffTime
     (
         -- * Calendar Duration
@@ -9,6 +11,7 @@
 import Data.Fixed
 import Data.Typeable
 import Data.Data
+import Control.DeepSeq
 import Data.Time.Calendar.CalendarDiffDays
 import Data.Time.Clock.Internal.NominalDiffTime
 
@@ -25,6 +28,9 @@
     -- ^ @since 1.9.2
 #endif
     )
+
+instance NFData CalendarDiffTime where
+    rnf (CalendarDiffTime m t) = rnf m `seq` rnf t `seq` ()
 
 -- | Additive
 instance Semigroup CalendarDiffTime where
diff --git a/lib/Data/Time/LocalTime/Internal/LocalTime.hs b/lib/Data/Time/LocalTime/Internal/LocalTime.hs
--- a/lib/Data/Time/LocalTime/Internal/LocalTime.hs
+++ b/lib/Data/Time/LocalTime/Internal/LocalTime.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE Safe #-}
 {-# OPTIONS -fno-warn-orphans #-}
 
 module Data.Time.LocalTime.Internal.LocalTime
diff --git a/lib/Data/Time/LocalTime/Internal/TimeOfDay.hs b/lib/Data/Time/LocalTime/Internal/TimeOfDay.hs
--- a/lib/Data/Time/LocalTime/Internal/TimeOfDay.hs
+++ b/lib/Data/Time/LocalTime/Internal/TimeOfDay.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE Safe #-}
+
 module Data.Time.LocalTime.Internal.TimeOfDay
     (
     -- * Time of day
@@ -37,7 +39,7 @@
     } deriving (Eq, Ord, Data, Typeable)
 
 instance NFData TimeOfDay where
-    rnf (TimeOfDay h m s) = rnf h `seq` rnf m `seq` s `seq` () -- FIXME: Data.Fixed had no NFData instances yet at time of writing
+    rnf (TimeOfDay h m s) = rnf h `seq` rnf m `seq` rnf s `seq` ()
 
 -- | Hour zero
 midnight :: TimeOfDay
diff --git a/lib/Data/Time/LocalTime/Internal/TimeZone.hs b/lib/Data/Time/LocalTime/Internal/TimeZone.hs
--- a/lib/Data/Time/LocalTime/Internal/TimeZone.hs
+++ b/lib/Data/Time/LocalTime/Internal/TimeZone.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE Safe #-}
 {-# LANGUAGE ForeignFunctionInterface #-}
 
 module Data.Time.LocalTime.Internal.TimeZone
diff --git a/lib/Data/Time/LocalTime/Internal/ZonedTime.hs b/lib/Data/Time/LocalTime/Internal/ZonedTime.hs
--- a/lib/Data/Time/LocalTime/Internal/ZonedTime.hs
+++ b/lib/Data/Time/LocalTime/Internal/ZonedTime.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE Safe #-}
 {-# OPTIONS -fno-warn-orphans #-}
 
 module Data.Time.LocalTime.Internal.ZonedTime
diff --git a/test/main/Test/Types.hs b/test/main/Test/Types.hs
--- a/test/main/Test/Types.hs
+++ b/test/main/Test/Types.hs
@@ -1,26 +1,36 @@
-module Test.Types(CheckInstances) where
+module Test.Types() where
 
+import Control.DeepSeq
 import Data.Data
+import Data.Ix
 import Data.Time
+import Data.Time.Calendar.Month
+import Data.Time.Calendar.Quarter
 import Data.Time.Clock.System
 import Data.Time.Clock.TAI
 
-class (Typeable t, Data t) => CheckDataInstances t
-class (Typeable t, Data t, Eq t) => CheckInstances t
+class (Typeable t, Data t, NFData t) => CheckDataInstances t
+class (Typeable t, Data t, NFData t, Eq t) => CheckEqInstances t
+class (Typeable t, Data t, NFData t, Eq t, Ord t) => CheckOrdInstances t
+class (Typeable t, Data t, NFData t, Eq t, Ord t, Ix t, Enum t) => CheckEnumInstances t
+class (Typeable t, Data t, NFData t, Eq t, Ord t, Ix t, Enum t, Bounded t) => CheckBoundedInstances t
 
-instance CheckInstances UTCTime
-instance CheckInstances NominalDiffTime
+instance CheckOrdInstances UTCTime
+instance CheckOrdInstances NominalDiffTime
 
-instance CheckInstances Day
-instance CheckInstances DayOfWeek
-instance CheckInstances TimeOfDay
-instance CheckInstances LocalTime
-instance CheckInstances TimeZone
+instance CheckEnumInstances Day
+instance CheckEnumInstances DayOfWeek
+instance CheckOrdInstances TimeOfDay
+instance CheckOrdInstances LocalTime
+instance CheckOrdInstances TimeZone
 instance CheckDataInstances ZonedTime
-instance CheckInstances CalendarDiffDays
-instance CheckInstances CalendarDiffTime
+instance CheckEqInstances CalendarDiffDays
+instance CheckEqInstances CalendarDiffTime
+instance CheckEnumInstances Month
+instance CheckEnumInstances Quarter
+instance CheckBoundedInstances QuarterOfYear
 
-instance CheckInstances SystemTime
+instance CheckOrdInstances SystemTime
 
-instance CheckInstances AbsoluteTime
-instance CheckInstances UniversalTime
+instance CheckOrdInstances AbsoluteTime
+instance CheckOrdInstances UniversalTime
diff --git a/time.cabal b/time.cabal
--- a/time.cabal
+++ b/time.cabal
@@ -1,5 +1,5 @@
 name:           time
-version:        1.11
+version:        1.11.1
 stability:      stable
 license:        BSD3
 license-file:   LICENSE