diff --git a/Data/Time/LocalTime/TimeZone/Internal/TimeVersion.hs b/Data/Time/LocalTime/TimeZone/Internal/TimeVersion.hs
deleted file mode 100644
--- a/Data/Time/LocalTime/TimeZone/Internal/TimeVersion.hs
+++ /dev/null
@@ -1,40 +0,0 @@
-{-# LANGUAGE CPP #-}
-
--- | Functions that depend on the version of the @time@ library
-
-module Data.Time.LocalTime.TimeZone.Internal.TimeVersion
-(
-   mapBuiltTime
- , mapFormatCharacter
-)
-where
-
-#if MIN_VERSION_time(1,6,0)
-
-mapBuiltTime :: Functor f => (a -> b) -> f a -> f b
-mapBuiltTime = fmap
-
-#else
-
-mapBuiltTime :: a -> a
-mapBuiltTime = id
-
-#endif
-
-#if MIN_VERSION_time(1,9,1)
-
-mapFormatCharacter :: (a -> b) -> Maybe (x -> b -> String) -> Maybe (x -> a -> String)
-mapFormatCharacter f = fmap (\g x -> g x . f)
-
-#elif MIN_VERSION_time(1,8,0)
-
-mapFormatCharacter ::
-  (a -> b) -> (c -> d -> e -> b -> z) -> c -> d -> e -> a -> z
-mapFormatCharacter f g locale mpado mwidth = g locale mpado mwidth . f
-
-#else
-
-mapFormatCharacter :: (a -> b) -> (c -> d -> b -> z) -> c -> d -> a -> z
-mapFormatCharacter f g locale mpado = g locale mpado . f
-
-#endif
diff --git a/Data/Time/LocalTime/TimeZone/Series.hs b/Data/Time/LocalTime/TimeZone/Series.hs
--- a/Data/Time/LocalTime/TimeZone/Series.hs
+++ b/Data/Time/LocalTime/TimeZone/Series.hs
@@ -32,21 +32,23 @@
                   ZonedTime(ZonedTime),
                   utcToLocalTime, localTimeToUTC)
 #if MIN_VERSION_time(1,9,1)
-import Data.Time.Format.Internal (FormatTime(formatCharacter), ParseTime(buildTime))
+import Data.Time.Format.Internal
+  ( FormatTime(formatCharacter)
+  , ParseTime( buildTime
+             , parseTimeSpecifier
+             , substituteTimeSpecifier
+             )
+  )
 #else
 import Data.Time (FormatTime(formatCharacter), ParseTime(buildTime))
 #endif
 import Data.List (partition)
 import Data.Maybe (listToMaybe, fromMaybe)
+import Data.Proxy (Proxy(Proxy))
 import Data.Typeable (Typeable)
 import Control.Arrow (first)
 import Control.DeepSeq (NFData(..))
 
--- Conditional import, depending on the version of the time library,
--- controlled by cabal flag:
-import Data.Time.LocalTime.TimeZone.Internal.TimeVersion (mapBuiltTime,
-  mapFormatCharacter)
-
 -- $abouttzs
 -- A @TimeZoneSeries@ describes a timezone with a set of 'TimeZone'
 -- objects. Each @TimeZone@ object describes the clock setting in the
@@ -93,7 +95,20 @@
 
 instance ParseTime TimeZoneSeries where
   buildTime locale = mapBuiltTime (flip TimeZoneSeries []) . buildTime locale
+#if MIN_VERSION_time(1,9,1)
+  parseTimeSpecifier _ = parseTimeSpecifier (Proxy :: Proxy TimeZone)
+  substituteTimeSpecifier _ =
+    substituteTimeSpecifier (Proxy :: Proxy TimeZone)
+#endif
 
+#if MIN_VERSION_time(1,6,0)
+mapBuiltTime :: Functor f => (a -> b) -> f a -> f b
+mapBuiltTime = fmap
+#else
+mapBuiltTime :: a -> a
+mapBuiltTime = id
+#endif
+
 -- | The latest non-summer @TimeZone@ in a @TimeZoneSeries@ is in some
 -- sense representative of the timezone.
 latestNonSummer :: TimeZoneSeries -> TimeZone
@@ -107,6 +122,19 @@
     fmap (mapFormatCharacter latestNonSummer) .
     formatCharacter
 
+#if MIN_VERSION_time(1,9,1)
+mapFormatCharacter ::
+  (a -> b) -> Maybe (x -> b -> String) -> Maybe (x -> a -> String)
+mapFormatCharacter f = fmap (\g x -> g x . f)
+#elif MIN_VERSION_time(1,8,0)
+mapFormatCharacter ::
+  (a -> b) -> (c -> d -> e -> b -> z) -> c -> d -> e -> a -> z
+mapFormatCharacter f g locale mpado mwidth = g locale mpado mwidth . f
+#else
+mapFormatCharacter :: (a -> b) -> (c -> d -> b -> z) -> c -> d -> a -> z
+mapFormatCharacter f g locale mpado = g locale mpado . f
+#endif
+
 -- | Given a timezone represented by a @TimeZoneSeries@, and a @UTCTime@,
 -- provide the state of the timezone's clocks at that time.
 timeZoneFromSeries :: TimeZoneSeries -> UTCTime -> TimeZone
@@ -183,6 +211,11 @@
 
 instance ParseTime ZoneSeriesTime where
   buildTime locale = mapBuiltTime zonedTimeToZoneSeriesTime . buildTime locale
+#if MIN_VERSION_time(1,9,1)
+  parseTimeSpecifier _ = parseTimeSpecifier (Proxy :: Proxy ZonedTime)
+  substituteTimeSpecifier _ =
+    substituteTimeSpecifier (Proxy :: Proxy ZonedTime)
+#endif
 
 instance FormatTime ZoneSeriesTime where
   formatCharacter =
diff --git a/LICENSE b/LICENSE
--- a/LICENSE
+++ b/LICENSE
@@ -1,4 +1,4 @@
-Copyright (c) 2010-2018 Yitzchak Gale. All rights reserved.
+Copyright (c) 2010-2021 Yitzchak Gale. All rights reserved.
 
 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -43,7 +43,7 @@
 packages for more information about reading and creating Olson
 timezone files.
 
-Copyright (c) 2010-2018 Yitzchak Gale. All rights reserved.
+Copyright (c) 2010-2021 Yitzchak Gale. All rights reserved.
 
 For licensing information, see the BSD3-style license in the file
 LICENSE that was originally distributed by the author together with
diff --git a/timezone-series.cabal b/timezone-series.cabal
--- a/timezone-series.cabal
+++ b/timezone-series.cabal
@@ -1,5 +1,5 @@
 Name:                timezone-series
-Version:             0.1.9
+Version:             0.1.13
 Synopsis:            Enhanced timezone handling for Data.Time
 Description:         This package endows Data.Time, from the time
                      package, with several data types and functions
@@ -14,7 +14,7 @@
 License-file:        LICENSE
 Author:              Yitzchak Gale
 Maintainer:          yitz@sefer.org
-Copyright:           Copyright (c) 2010-2018 Yitzchak Gale. All rights reserved.
+Copyright:           Copyright (c) 2010-2021 Yitzchak Gale. All rights reserved.
 Category:            Data
 Build-type:          Simple
 Extra-source-files:  README.md
@@ -29,8 +29,7 @@
   Default-language:    Haskell2010
   Hs-source-dirs:      .
   Exposed-modules:     Data.Time.LocalTime.TimeZone.Series
-  Other-modules:       Data.Time.LocalTime.TimeZone.Internal.TimeVersion
   Default-extensions:  DeriveDataTypeable
   Build-depends:       base >= 4.4 && < 5
                      , deepseq
-                     , time (>= 1.1.4 && < 1.9) || (>= 1.9.1 && < 1.10)
+                     , time (>= 1.1.4 && < 1.9) || (>= 1.9.1 && < 1.13)