diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -21,6 +21,16 @@
 pattern Base64Url :: Text -> Text
 pattern Base64Unpadded :: Text -> Text
 pattern Base64UrlUnpadded :: Text -> Text
+
+-- additionally if using >=base64-0.3
+
+Base64Lenient :: ByteString -> ByteString
+Base64UrlLenient :: ByteString -> ByteString
+
+-- and
+
+Base64Lenient :: Text -> Text
+Base64UrlLenient :: Text -> Text
 ```
 
 These provide a convenient high level interface for passing Base64 encoded values.
@@ -44,6 +54,15 @@
 _Base64Unpadded :: Prism' Text Text
 _Base64UrlUnpadded :: Prism' Text Text
 
+-- additionally if using >=base64-0.3
+
+_Base64Lenient :: Iso' ByteString ByteString
+_Base64UrlLenient :: Iso' ByteString ByteString
+
+-- and
+
+_Base64Lenient :: Iso' Text Text
+_Base64UrlLenient :: Iso' Text Text
 ```
 
 If a particular structure has a `Lens` into some `Text` or `ByteString` value they might want to encode (or decode), then composing such a `Lens` with these `Prisms` yields an affine `Traversal`, resulting in a structure which has the focus of its `Lens` encoded as or decoded from Base64(-url). All one needs to do is compose their optics:
diff --git a/base64-lens.cabal b/base64-lens.cabal
--- a/base64-lens.cabal
+++ b/base64-lens.cabal
@@ -1,7 +1,7 @@
 cabal-version:       1.24
 
 name:                base64-lens
-version:             0.1.0.1
+version:             0.1.0.3
 synopsis:            Optics for the Base64 library
 description:
   Prisms and pattern synonyms for the Base64 library
@@ -37,10 +37,10 @@
                      , Data.Text.Encoding.Base64.Lens
 
   build-depends:       base       >=4.10 && <5
-                     , base64     >=0.2  && <0.3
+                     , base64     >=0.2  && <0.4
                      , bytestring >=0.10 && <0.11
                      , lens       >=4.0  && <4.19
-                     , text
+                     , text       >=1.2  && <1.3
 
   hs-source-dirs:      src
   default-language:    Haskell2010
diff --git a/src/Data/ByteString/Base64/Lens.hs b/src/Data/ByteString/Base64/Lens.hs
--- a/src/Data/ByteString/Base64/Lens.hs
+++ b/src/Data/ByteString/Base64/Lens.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP #-}
 {-# LANGUAGE PatternSynonyms #-}
 {-# LANGUAGE ViewPatterns #-}
 -- |
@@ -9,7 +10,7 @@
 -- Stability	: Experimental
 -- Portability	: non-portable
 --
--- This module contains 'Control.Lens.Type.Prism's for Base64-encoding and
+-- This module contains 'Prism''s for Base64-encoding and
 -- decoding 'ByteString' values.
 --
 module Data.ByteString.Base64.Lens
@@ -18,11 +19,19 @@
 , _Base64Url
 , _Base64Unpadded
 , _Base64UrlUnpadded
+#if MIN_VERSION_base64(0,3,0)
+, _Base64Lenient
+, _Base64UrlLenient
+#endif
   -- * Patterns
 , pattern Base64
 , pattern Base64Url
 , pattern Base64Unpadded
 , pattern Base64UrlUnpadded
+#if MIN_VERSION_base64(0,3,0)
+, pattern Base64Lenient
+, pattern Base64UrlLenient
+#endif
 ) where
 
 
@@ -45,7 +54,7 @@
 -- -------------------------------------------------------------------------- --
 -- Optics
 
--- | A 'Control.Lens.Type.Prism' into the Base64 encoding of a 'ByteString' value
+-- | A 'Prism'' into the Base64 encoding of a 'ByteString' value
 --
 -- >>> _Base64 # "Sun"
 -- "U3Vu"
@@ -54,12 +63,12 @@
 -- Just "Sun"
 --
 _Base64 :: Prism' ByteString ByteString
-_Base64 = prism' B64.encodeBase64 $ \s -> case B64.decodeBase64 s of
+_Base64 = prism' B64.encodeBase64' $ \s -> case B64.decodeBase64 s of
     Left _ -> Nothing
     Right a -> Just a
 {-# INLINE _Base64 #-}
 
--- | A 'Control.Lens.Type.Prism' into the Base64-url encoding of a 'ByteString' value
+-- | A 'Prism'' into the Base64url encoding of a 'ByteString' value
 --
 -- >>> _Base64Url # "Sun"
 -- "U3Vu"
@@ -68,12 +77,12 @@
 -- Just "<<???>>"
 --
 _Base64Url :: Prism' ByteString ByteString
-_Base64Url = prism' B64U.encodeBase64 $ \s -> case B64U.decodeBase64 s of
+_Base64Url = prism' B64U.encodeBase64' $ \s -> case B64U.decodeBase64 s of
     Left _ -> Nothing
     Right a -> Just a
 {-# INLINE _Base64Url #-}
 
--- | A 'Control.Lens.Type.Prism' into the unpadded Base64 encoding of a
+-- | A 'Prism'' into the unpadded Base64 encoding of a
 -- 'ByteString' value
 --
 -- Please note that unpadded variants should only be used
@@ -87,12 +96,12 @@
 -- Just "Sun"
 --
 _Base64Unpadded :: Prism' ByteString ByteString
-_Base64Unpadded = prism' B64.encodeBase64Unpadded $ \s -> case B64.decodeBase64Unpadded s of
+_Base64Unpadded = prism' B64.encodeBase64Unpadded' $ \s -> case B64.decodeBase64Unpadded s of
     Left _ -> Nothing
     Right a -> Just a
 {-# INLINE _Base64Unpadded #-}
 
--- | A 'Control.Lens.Type.Prism' into the Base64-url encoding of a 'ByteString' value
+-- | A 'Prism'' into the Base64url encoding of a 'ByteString' value
 --
 -- Please note that unpadded variants should only be used
 -- when assumptions about the data can be made. In particular, if the length of
@@ -105,11 +114,43 @@
 -- Just "<<??>>"
 --
 _Base64UrlUnpadded :: Prism' ByteString ByteString
-_Base64UrlUnpadded = prism' B64U.encodeBase64Unpadded $ \s -> case B64U.decodeBase64Unpadded s of
+_Base64UrlUnpadded = prism' B64U.encodeBase64Unpadded' $ \s -> case B64U.decodeBase64Unpadded s of
     Left _ -> Nothing
     Right a -> Just a
 {-# INLINE _Base64UrlUnpadded #-}
 
+#if MIN_VERSION_base64(0,3,0)
+-- | An 'Iso'' into the Base64 encoding of a 'ByteString' value
+-- using lenient decoding.
+--
+--
+-- _Note:_ This is not a lawful 'Iso'.
+--
+-- >>> "Sun" ^. _Base64Lenient
+-- "U3Vu"
+--
+-- >>> "U3Vu" ^. from _Base64Lenient
+-- "Sun"
+--
+_Base64Lenient :: Iso' ByteString ByteString
+_Base64Lenient = iso B64.encodeBase64' B64.decodeBase64Lenient
+
+-- | An 'Iso'' into the Base64url encoding of a 'ByteString' value
+-- using lenient decoding.
+--
+--
+-- _Note:_ This is not a lawful 'Iso'.
+--
+-- >>> "<<??>>" ^. _Base64UrlLenient
+-- "PDw_Pz4-"
+--
+-- >>> "PDw_Pz4-" ^. from _Base64UrlLenient
+-- "<<??>>"
+--
+_Base64UrlLenient :: Iso' ByteString ByteString
+_Base64UrlLenient = iso B64U.encodeBase64' B64U.decodeBase64Lenient
+#endif
+
 -- -------------------------------------------------------------------------- --
 -- Patterns
 
@@ -136,3 +177,19 @@
 pattern Base64UrlUnpadded :: ByteString -> ByteString
 pattern Base64UrlUnpadded a <- (preview _Base64UrlUnpadded -> Just a) where
     Base64UrlUnpadded a = _Base64UrlUnpadded # a
+
+#if MIN_VERSION_base64(0,3,0)
+-- | Bidirectional pattern synonym for leniently Base64-encoded 'ByteString' values
+--
+pattern Base64Lenient :: ByteString -> ByteString
+pattern Base64Lenient a <- (view (from _Base64Lenient) -> a) where
+    Base64Lenient a = view _Base64Lenient a
+{-# COMPLETE Base64Lenient #-}
+
+-- | Bidirectional pattern synonym for leniently Base64-encoded 'ByteString' values
+--
+pattern Base64UrlLenient :: ByteString -> ByteString
+pattern Base64UrlLenient a <- (view (from _Base64UrlLenient) -> a) where
+    Base64UrlLenient a = view _Base64UrlLenient a
+{-# COMPLETE Base64UrlLenient #-}
+#endif
diff --git a/src/Data/Text/Encoding/Base64/Lens.hs b/src/Data/Text/Encoding/Base64/Lens.hs
--- a/src/Data/Text/Encoding/Base64/Lens.hs
+++ b/src/Data/Text/Encoding/Base64/Lens.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP #-}
 {-# LANGUAGE PatternSynonyms #-}
 {-# LANGUAGE ViewPatterns #-}
 -- |
@@ -9,7 +10,7 @@
 -- Stability	: Experimental
 -- Portability	: non-portable
 --
--- This module contains 'Control.Lens.Type.Prism's Base64-encoding and
+-- This module contains 'Prism's Base64-encoding and
 -- decoding 'Text' values.
 --
 module Data.Text.Encoding.Base64.Lens
@@ -18,14 +19,21 @@
 , _Base64Url
 , _Base64Unpadded
 , _Base64UrlUnpadded
+#if MIN_VERSION_base64(0,3,0)
+, _Base64Lenient
+, _Base64UrlLenient
+#endif
   -- * Patterns
 , pattern Base64
 , pattern Base64Url
 , pattern Base64Unpadded
 , pattern Base64UrlUnpadded
+#if MIN_VERSION_base64(0,3,0)
+, pattern Base64Lenient
+, pattern Base64UrlLenient
+#endif
 ) where
 
-
 import Control.Lens
 
 import Data.Text (Text)
@@ -44,7 +52,7 @@
 -- -------------------------------------------------------------------------- --
 -- Optics
 
--- | A 'Control.Lens.Type.Prism' into the Base64 encoding of a 'Text' value.
+-- | A 'Prism' into the Base64 encoding of a 'Text' value.
 --
 -- >>> _Base64 # "Sun"
 -- "U3Vu"
@@ -58,7 +66,7 @@
     Right a -> Just a
 {-# INLINE _Base64 #-}
 
--- | A 'Control.Lens.Type.Prism' into the Base64-url encoding of a 'Text' value.
+-- | A 'Prism' into the Base64-url encoding of a 'Text' value.
 --
 -- >>> _Base64Url # "Sun"
 -- "U3Vu"
@@ -72,7 +80,7 @@
     Right a -> Just a
 {-# INLINE _Base64Url #-}
 
--- | A 'Control.Lens.Type.Prism' into the unpadded Base64 encoding of a
+-- | A 'Prism' into the unpadded Base64 encoding of a
 -- 'Text' value.
 --
 -- Please note that unpadded variants should only be used
@@ -91,7 +99,7 @@
     Right a -> Just a
 {-# INLINE _Base64Unpadded #-}
 
--- | A 'Control.Lens.Type.Prism' into the Base64-url encoding of a 'Text' value.
+-- | A 'Prism' into the Base64-url encoding of a 'Text' value.
 --
 -- Please note that unpadded variants should only be used
 -- when assumptions about the data can be made. In particular, if the length of
@@ -109,29 +117,77 @@
     Right a -> Just a
 {-# INLINE _Base64UrlUnpadded #-}
 
+#if MIN_VERSION_base64(0,3,0)
+-- | An 'Iso'' into the Base64 encoding of a 'Text' value
+-- using lenient decoding.
+--
+--
+-- _Note:_ This is not a lawful 'Iso'.
+--
+-- >>> "Sun" ^. _Base64Lenient
+-- "U3Vu"
+--
+-- >>> "U3Vu" ^. from _Base64Lenient
+-- "Sun"
+--
+_Base64Lenient :: Iso' Text Text
+_Base64Lenient = iso B64T.encodeBase64 B64T.decodeBase64Lenient
+
+-- | An 'Iso'' into the Base64url encoding of a 'Text' value
+-- using lenient decoding.
+--
+--
+-- _Note:_ This is not a lawful 'Iso'.
+--
+-- >>> "<<??>>" ^. _Base64UrlLenient
+-- "PDw_Pz4-"
+--
+-- >>> "PDw_Pz4-" ^. from _Base64UrlLenient
+-- "<<??>>"
+--
+_Base64UrlLenient :: Iso' Text Text
+_Base64UrlLenient = iso B64TU.encodeBase64 B64TU.decodeBase64Lenient
+#endif
+
 -- -------------------------------------------------------------------------- --
 -- Patterns
 
--- | Bidirectional pattern synonym for base64-encoded 'Text' values.
+-- | Unidirectional pattern synonym for base64-encoded 'Text' values.
 --
 pattern Base64 :: Text -> Text
-pattern Base64 a <- (preview _Base64 -> Just a)
-  where Base64 a = _Base64 # a
+pattern Base64 a <- (preview _Base64 -> Just a) where
+    Base64 a = _Base64 # a
 
--- | Bidirectional pattern synonym for base64url-encoded 'Text' values.
+-- | Unidirectional pattern synonym for base64url-encoded 'Text' values.
 --
 pattern Base64Url :: Text -> Text
-pattern Base64Url a <- (preview _Base64Url -> Just a)
-  where Base64Url a = _Base64Url # a
+pattern Base64Url a <- (preview _Base64Url -> Just a) where
+    Base64Url a = _Base64Url # a
 
--- | Bidirectional pattern synonym for unpadded base64-encoded 'Text' values.
+-- | Unidirectional pattern synonym for unpadded base64-encoded 'Text' values.
 --
 pattern Base64Unpadded :: Text -> Text
-pattern Base64Unpadded a <- (preview _Base64Unpadded -> Just a)
-  where Base64Unpadded a = _Base64Unpadded # a
+pattern Base64Unpadded a <- (preview _Base64Unpadded -> Just a) where
+    Base64Unpadded a = _Base64Unpadded # a
 
--- | Bidirectional pattern synonym for unpadded base64url-encoded 'Text' values.
+-- | Unidirectional pattern synonym for unpadded base64url-encoded 'Text' values.
 --
 pattern Base64UrlUnpadded :: Text -> Text
-pattern Base64UrlUnpadded a <- (preview _Base64UrlUnpadded -> Just a)
-  where Base64UrlUnpadded a = _Base64UrlUnpadded # a
+pattern Base64UrlUnpadded a <- (preview _Base64UrlUnpadded -> Just a) where
+    Base64UrlUnpadded a = _Base64UrlUnpadded # a
+
+#if MIN_VERSION_base64(0,3,0)
+-- | Bidirectional pattern synonym for leniently Base64-encoded 'Text' values
+--
+pattern Base64Lenient :: Text -> Text
+pattern Base64Lenient a <- (view (from _Base64Lenient) -> a) where
+    Base64Lenient a = view _Base64Lenient a
+{-# COMPLETE Base64Lenient #-}
+
+-- | Bidirectional pattern synonym for leniently Base64-encoded 'Text' values
+--
+pattern Base64UrlLenient :: Text -> Text
+pattern Base64UrlLenient a <- (view (from _Base64UrlLenient) -> a) where
+    Base64UrlLenient a = view _Base64UrlLenient a
+{-# COMPLETE Base64UrlLenient #-}
+#endif