diff --git a/src/System/Logger/Backend/ColorOption.hs b/src/System/Logger/Backend/ColorOption.hs
index e6e9479..e649250 100644
--- a/src/System/Logger/Backend/ColorOption.hs
+++ b/src/System/Logger/Backend/ColorOption.hs
@@ -51,15 +51,17 @@ module System.Logger.Backend.ColorOption
 import Configuration.Utils
 
 import Control.DeepSeq
+import Control.Lens
 import Control.Monad.Except
 
-import qualified Data.CaseInsensitive as CI
+import Data.Char (toLower)
 #if ! MIN_VERSION_base(4,8,0)
 import Data.Monoid
 #endif
 import Data.Monoid.Unicode
 import Data.String
 import qualified Data.Text as T
+import Data.Text.Lens
 import Data.Typeable
 
 import GHC.Generics
@@ -85,10 +87,10 @@ data ColorOption
 instance NFData ColorOption
 
 readColorOption
-    ∷ (Monad m, Eq a, Show a, CI.FoldCase a, IsString a, IsString e, Monoid e, MonadError e m)
+    ∷ (Monad m, Eq a, Show a, IsText a, IsString a, IsString e, Monoid e, MonadError e m)
     ⇒ a
     → m ColorOption
-readColorOption x = case CI.mk x of
+readColorOption x = case runIdentity (text (pure . toLower) x) of
     "auto" → return ColorAuto
     "false" → return ColorFalse
     "true" → return ColorTrue
diff --git a/src/System/Logger/Backend/Handle.hs b/src/System/Logger/Backend/Handle.hs
index ffb3e1d..0253f98 100644
--- a/src/System/Logger/Backend/Handle.hs
+++ b/src/System/Logger/Backend/Handle.hs
@@ -70,7 +70,7 @@ import Control.Monad.Except
 import Control.Monad.Trans.Control
 import Control.Monad.Writer
 
-import qualified Data.CaseInsensitive as CI
+import Data.Char (toLower)
 import qualified Data.List as L
 import Data.Monoid.Unicode
 import Data.String
@@ -106,17 +106,18 @@ data LoggerHandleConfig
 instance NFData LoggerHandleConfig
 
 readLoggerHandleConfig
-    ∷ (MonadError e m, Eq a, Show a, CI.FoldCase a, IsText a, IsString e, Monoid e)
+    ∷ (MonadError e m, Eq a, Show a, IsText a, IsString e, Monoid e)
     ⇒ a
     → m LoggerHandleConfig
-readLoggerHandleConfig x = case CI.mk tx of
+readLoggerHandleConfig x = case foldedTx of
     "stdout" → return StdOut
     "stderr" → return StdErr
-    _ | CI.mk (L.take 5 tx) ≡ "file:" → return $ FileHandle (L.drop 5 tx)
+    _ | L.take 5 foldedTx ≡ "file:" → return $ FileHandle (L.drop 5 tx)
     e → throwError $ "unexpected logger handle value: "
         ⊕ fromString (show e)
         ⊕ ", expected \"stdout\", \"stderr\", or \"file:<FILENAME>\""
   where
+    foldedTx = runIdentity $ text (pure . toLower) tx
     tx = packed # x
 
 loggerHandleConfigText
@@ -217,7 +218,7 @@ withHandleBackend = withHandleBackend_ id
 
 withHandleBackend_
     ∷ (MonadIO m, MonadBaseControl IO m)
-    ⇒ (msg -> T.Text)
+    ⇒ (msg → T.Text)
         -- ^ formatting function for the log message
     → HandleBackendConfig
     → (LoggerBackend msg → m α)
@@ -241,7 +242,7 @@ handleBackend = handleBackend_ id
 {-# INLINE handleBackend #-}
 
 handleBackend_
-    ∷ (msg -> T.Text)
+    ∷ (msg → T.Text)
         -- ^ formatting function for the log message
     → Handle
     → Bool
diff --git a/src/System/Logger/Types.hs b/src/System/Logger/Types.hs
index 9ae02ee..86498aa 100644
--- a/src/System/Logger/Types.hs
+++ b/src/System/Logger/Types.hs
@@ -105,7 +105,7 @@ import Control.Monad.Trans.Trace
 import Control.Monad.Writer
 import Control.Monad.Unicode
 
-import qualified Data.CaseInsensitive as CI
+import Data.Char (toLower)
 import Data.Monoid.Unicode
 import Data.String
 import qualified Data.Text as T
@@ -135,10 +135,10 @@ data LogLevel
 instance NFData LogLevel
 
 readLogLevel
-    ∷ (MonadError e m, Eq a, Show a, CI.FoldCase a, IsString a, IsString e, Monoid e)
+    ∷ (MonadError e m, Eq a, Show a, IsText a, IsString a, IsString e, Monoid e)
     ⇒ a
     → m LogLevel
-readLogLevel x = case CI.mk x of
+readLogLevel x = case runIdentity (text (pure . toLower) x) of
     "quiet" → return Quiet
     "error" → return Error
     "warn" → return Warn
@@ -196,10 +196,10 @@ logPolicyText LogPolicyRaise = "raise"
 logPolicyText LogPolicyBlock = "block"
 
 readLogPolicy
-    ∷ (MonadError e m, Eq a, Show a, CI.FoldCase a, IsText a, IsString e, Monoid e)
+    ∷ (MonadError e m, Eq a, Show a, IsText a, IsString e, Monoid e)
     ⇒ a
     → m LogPolicy
-readLogPolicy x = case CI.mk tx of
+readLogPolicy x = case foldedTx of
     "discard" → return LogPolicyDiscard
     "raise" → return LogPolicyRaise
     "block" → return LogPolicyBlock
@@ -207,6 +207,7 @@ readLogPolicy x = case CI.mk tx of
         $ "invalid log policy value " ⊕ fromString (show e) ⊕ ";"
         ⊕ " the log policy value must be one of \"discard\", \"raise\", or \"block\""
   where
+    foldedTx = runIdentity $ text (pure . toLower) tx
     tx = packed # x
 
 instance ToJSON LogPolicy where
diff --git a/yet-another-logger.cabal b/yet-another-logger.cabal
index bd702a5..8c9182a 100644
--- a/yet-another-logger.cabal
+++ b/yet-another-logger.cabal
@@ -96,7 +96,6 @@ Library
         base == 4.*,
         base-unicode-symbols >= 0.2,
         bytestring >= 0.10,
-        case-insensitive >= 1.2,
         clock >= 0.4,
         configuration-tools >= 0.2.8,
         deepseq >= 1.3,