diff --git a/GHC/HandleEncoding.hs b/GHC/HandleEncoding.hs
new file mode 100644
--- /dev/null
+++ b/GHC/HandleEncoding.hs
@@ -0,0 +1,31 @@
+-- | See GHC #10762 and #15021.
+module GHC.HandleEncoding (configureHandleEncoding) where
+
+import GHC.IO.Encoding (textEncodingName)
+import System.Environment
+import System.IO
+
+-- | Handle GHC-specific character encoding flags, allowing us to control how
+-- GHC produces output regardless of OS.
+configureHandleEncoding :: IO ()
+configureHandleEncoding = do
+   env <- getEnvironment
+   case lookup "GHC_CHARENC" env of
+    Just "UTF-8" -> do
+     hSetEncoding stdout utf8
+     hSetEncoding stderr utf8
+    _ -> do
+     -- Avoid GHC erroring out when trying to display unhandled characters
+     hSetTranslit stdout
+     hSetTranslit stderr
+
+-- | Change the character encoding of the given Handle to transliterate
+-- on unsupported characters instead of throwing an exception
+hSetTranslit :: Handle -> IO ()
+hSetTranslit h = do
+    menc <- hGetEncoding h
+    case fmap textEncodingName menc of
+        Just name | '/' `notElem` name -> do
+            enc' <- mkTextEncoding $ name ++ "//TRANSLIT"
+            hSetEncoding h enc'
+        _ -> return ()
diff --git a/GHC/PackageDb.hs b/GHC/PackageDb.hs
--- a/GHC/PackageDb.hs
+++ b/GHC/PackageDb.hs
@@ -80,9 +80,7 @@
 import System.IO
 import System.IO.Error
 import GHC.IO.Exception (IOErrorType(InappropriateType))
-#if MIN_VERSION_base(4,10,0)
 import GHC.IO.Handle.Lock
-#endif
 import System.Directory
 
 
@@ -209,12 +207,7 @@
   }
 
 -- | Represents a lock of a package db.
-newtype PackageDbLock = PackageDbLock
-#if MIN_VERSION_base(4,10,0)
-  Handle
-#else
-  ()  -- no locking primitives available in base < 4.10
-#endif
+newtype PackageDbLock = PackageDbLock Handle
 
 -- | Acquire an exclusive lock related to package DB under given location.
 lockPackageDb :: FilePath -> IO PackageDbLock
@@ -222,8 +215,6 @@
 -- | Release the lock related to package DB.
 unlockPackageDb :: PackageDbLock -> IO ()
 
-#if MIN_VERSION_base(4,10,0)
-
 -- | Acquire a lock of given type related to package DB under given location.
 lockPackageDbWith :: LockMode -> FilePath -> IO PackageDbLock
 lockPackageDbWith mode file = do
@@ -273,15 +264,6 @@
 #endif
     hClose hnd
 
--- MIN_VERSION_base(4,10,0)
-#else
-
-lockPackageDb _file = return $ PackageDbLock ()
-unlockPackageDb _lock = return ()
-
--- MIN_VERSION_base(4,10,0)
-#endif
-
 -- | Mode to open a package db in.
 data DbMode = DbReadOnly | DbReadWrite
 
@@ -410,7 +392,7 @@
   -- shared lock on non-Windows platform because we update the database with an
   -- atomic rename, so readers will always see the database in a consistent
   -- state.
-#if MIN_VERSION_base(4,10,0) && defined(mingw32_HOST_OS)
+#if defined(mingw32_HOST_OS)
     bracket (lockPackageDbWith SharedLock file) unlockPackageDb $ \_ -> do
 #endif
       (, DbOpenReadOnly) <$> decodeFileContents
diff --git a/GHC/Serialized.hs b/GHC/Serialized.hs
--- a/GHC/Serialized.hs
+++ b/GHC/Serialized.hs
@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP #-}
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE RankNTypes, ScopedTypeVariables #-}
 {-# OPTIONS_GHC -fno-warn-name-shadowing #-}
@@ -34,16 +33,10 @@
 -- | If the 'Serialized' value contains something of the given type, then use the specified deserializer to return @Just@ that.
 -- Otherwise return @Nothing@.
 fromSerialized :: forall a. Typeable a => ([Word8] -> a) -> Serialized -> Maybe a
-#if MIN_VERSION_base(4,10,0)
 fromSerialized deserialize (Serialized the_type bytes)
   | the_type == rep = Just (deserialize bytes)
   | otherwise       = Nothing
   where rep = typeRep (Proxy :: Proxy a)
-#else
-fromSerialized deserialize (Serialized the_type bytes)
-  | the_type == typeOf (undefined :: a) = Just (deserialize bytes)
-  | otherwise                           = Nothing
-#endif
 
 -- | Use a 'Data' instance to implement a serialization scheme dual to that of 'deserializeWithData'
 serializeWithData :: Data a => a -> [Word8]
diff --git a/changelog.md b/changelog.md
--- a/changelog.md
+++ b/changelog.md
@@ -1,3 +1,27 @@
+## 8.6.1  *August 2018*
+
+  * Bundled with GHC 8.6.1
+
+## 8.4.2  *April 2018*
+
+  * Bundled with GHC 8.4.2
+	
+## 8.4.1  *March 2018*
+
+  * Bundled with GHC 8.4.1
+
+## 8.2.2  *November 2018*
+
+  * Bundled with GHC 8.2.2
+
+## 8.2.1  *July 2017*
+
+  * Bundled with GHC 8.2.1
+
+## 8.0.2  *January 2017*
+
+  * Bundled with GHC 8.0.2
+
 ## 8.0.1  *May 2016*
 
   * Bundled with GHC 8.0.1
diff --git a/ghc-boot.cabal b/ghc-boot.cabal
--- a/ghc-boot.cabal
+++ b/ghc-boot.cabal
@@ -1,6 +1,6 @@
 cabal-version:  1.22
 name:           ghc-boot
-version:        8.4.4
+version:        8.6.1
 
 license:        BSD3
 license-file:   LICENSE
@@ -37,10 +37,11 @@
             GHC.PackageDb
             GHC.Serialized
             GHC.ForeignSrcLang
+            GHC.HandleEncoding
 
-    build-depends: base       >= 4.8 && < 4.12,
+    build-depends: base       >= 4.10 && < 4.13,
                    binary     == 0.8.*,
                    bytestring == 0.10.*,
                    directory  >= 1.2 && < 1.4,
                    filepath   >= 1.3 && < 1.5,
-                   ghc-boot-th == 8.4.4
+                   ghc-boot-th == 8.6.1