diff --git a/changelog.md b/changelog.md
--- a/changelog.md
+++ b/changelog.md
@@ -1,3 +1,11 @@
+#####   2.0.2
+    changes to Data.Time.Hora.Zone:
+    
+        remove redundant  ToTimeZone UTCTime (Tz (DatePart a)) instance: 
+        
+        use Data.Time.Hora.Part fromUtc'
+        
+
 #####   2.0.1
     include test data files
 
diff --git a/hora.cabal b/hora.cabal
--- a/hora.cabal
+++ b/hora.cabal
@@ -1,10 +1,10 @@
 name:                hora
-version:             2.0.1
+version:             2.0.2
 build-type:          Simple
 cabal-version:       >=1.10
 
 synopsis:            date time
-description:         pico precision * timestamps * timezones
+description:         pico precision * timestamps * timezones * format
 author:              Imants Cekusins
 maintainer:          Imants Cekusins
 category:            System, Time
diff --git a/src/Data/Time/Hora/Type.hs b/src/Data/Time/Hora/Type.hs
--- a/src/Data/Time/Hora/Type.hs
+++ b/src/Data/Time/Hora/Type.hs
@@ -18,6 +18,8 @@
 
 {- | serializeable structure for essential Date, Time parts
 
+may also be used to construct 'UTCTime'     
+
 see "Data.Time.Hora.Part" for conversion between 'UTCTime' and 'DatePart'   -}
 data DatePart a = DatePart {
     year::a,
@@ -83,7 +85,7 @@
 data Tz a = Tz TimeZone a  deriving (Show,Functor)
 
 
--- | 'TimeZone' | 'TimeZoneSeries' 
+-- | 'TimeZone' | 'TimeZoneSeries'
 class Tz' tz where
     tz'::tz -> UTCTime -> TimeZone
 
@@ -92,7 +94,9 @@
 
 instance Tz' TimeZoneSeries where
     tz' = timeZoneFromSeries
--- ^ see "Data.Time.Hora.Zone" re: 'TimeZoneSeries'
+{- ^ see "Data.Time.Hora.Zone" re: 'TimeZoneSeries'
+
+use of 'TimeZoneSeries' is preferred when converting from 'UTCTime' to 'DatePart' -}
 
 
 {- | second and fractions
diff --git a/src/Data/Time/Hora/Zone.hs b/src/Data/Time/Hora/Zone.hs
--- a/src/Data/Time/Hora/Zone.hs
+++ b/src/Data/Time/Hora/Zone.hs
@@ -15,29 +15,16 @@
 @       -}
 module Data.Time.Hora.Zone where
 
-import Data.Time.Clock
-import Data.Time.LocalTime.TimeZone.Series
 import Data.Time.Hora.Part
 import Data.Time.Hora.Type
 
 
-{-| convert __a__ to __b__ in specified 'TimeZone' -}
-class ToTimeZone a b where
-    toTimeZone::TimeZoneSeries -> a -> b
-    
-    
-instance Integral a => 
-            ToTimeZone UTCTime 
-                        (Tz (DatePart a)) where
-    toTimeZone series0 utc0 = 
-        let tz1 = timeZoneFromSeries series0 utc0
-        in fromUtc' tz1 utc0
--- ^ similar to 'fromUtc'' but safer around dates when e.g. Summer time changes   
-
-
-instance Integral a => 
-            ToTimeZone (Tz (DatePart a))
-                        (Maybe (Tz (DatePart a))) where
-    toTimeZone series0 dp0 = toUtc dp0 >>= Just . (toTimeZone series0)
 -- ^ convert 'DatePart' from one 'TimeZone' to another        
+toTimeZone::(TwoInt a b, Tz' tz) => 
+    tz -- ^ target timezone
+    -> (Tz (DatePart a)) -- ^ local (to source timezone) date & time 
+        -> (Maybe (Tz (DatePart b))) {- ^ local (to target timezone) date & time
+            
+                        'Nothing' if source date is invalid-} 
+toTimeZone series0 dp0 = toUtc dp0 >>= Just . (fromUtc' series0)
                 
diff --git a/test/Test/TestZone.hs b/test/Test/TestZone.hs
--- a/test/Test/TestZone.hs
+++ b/test/Test/TestZone.hs
@@ -5,10 +5,11 @@
 import Data.Time.Clock
 import Data.Time.LocalTime.TimeZone.Olson
 import Data.Time.LocalTime.TimeZone.Series
-import Data.Time.Hora.Zone
 import Data.Time.Hora.Stamp
 import Data.Time.Hora.Type
+import Data.Time.Hora.Part
 
+
 main::IO()
 main = hspec $ do
        describe "Test.TestZone" $ do
@@ -23,4 +24,4 @@
 
 
 ttz::TimeZoneSeries -> UTCTime -> Tz (DatePart Int)
-ttz = toTimeZone            
+ttz = fromUtc'