diff --git a/example/Main.hs b/example/Main.hs
index cf7667c6a..bf9fac6d0 100644
--- a/example/Main.hs
+++ b/example/Main.hs
@@ -32,7 +32,7 @@ import qualified Language.Haskell.LSP.Utility          as U
 import           Language.Haskell.LSP.VFS
 import           System.Exit
 import qualified System.Log.Logger                     as L
-import qualified Yi.Rope                               as Yi
+import qualified Data.Rope.UTF16                       as Rope
 
 
 -- ---------------------------------------------------------------------
@@ -195,7 +195,7 @@ reactor lf inp = do
         mdoc <- liftIO $ Core.getVirtualFileFunc lf doc
         case mdoc of
           Just (VirtualFile _version str) -> do
-            liftIO $ U.logs $ "reactor:processing NotDidChangeTextDocument: vf got:" ++ (show $ Yi.toString str)
+            liftIO $ U.logs $ "reactor:processing NotDidChangeTextDocument: vf got:" ++ (show $ Rope.toString str)
           Nothing -> do
             liftIO $ U.logs "reactor:processing NotDidChangeTextDocument: vf returned Nothing"
 
diff --git a/haskell-lsp.cabal b/haskell-lsp.cabal
index 557d19f17..90fd77aae 100644
--- a/haskell-lsp.cabal
+++ b/haskell-lsp.cabal
@@ -49,12 +49,12 @@ library
                      , mtl
                      , network-uri
                      , parsec
+                     , rope-utf16-splay >= 0.2
                      , sorted-list == 0.2.1.*
                      , stm
                      , text
                      , time
                      , unordered-containers
-                     , yi-rope
   hs-source-dirs:      src
   default-language:    Haskell2010
 
@@ -77,13 +77,13 @@ executable lsp-hello
                      , mtl
                      , network-uri
                      , parsec
+                     , rope-utf16-splay >= 0.2
                      , stm
                      , text
                      , time
                      , transformers
                      , unordered-containers
                      , vector
-                     , yi-rope
                      -- the package library. Comment this out if you want repl changes to propagate
                      , haskell-lsp
 
@@ -112,8 +112,8 @@ test-suite haskell-lsp-test
                      -- , hspec-jenkins
                      , lens >= 4.15.2
                      , network-uri
+                     , rope-utf16-splay >= 0.2
                      , sorted-list == 0.2.1.*
-                     , yi-rope
                      , haskell-lsp
                      , text
                      , stm
diff --git a/src/Language/Haskell/LSP/VFS.hs b/src/Language/Haskell/LSP/VFS.hs
index 4cd786247..905b5fb44 100644
--- a/src/Language/Haskell/LSP/VFS.hs
+++ b/src/Language/Haskell/LSP/VFS.hs
@@ -21,9 +21,7 @@ module Language.Haskell.LSP.VFS
   -- * for tests
   , applyChanges
   , applyChange
-  , deleteChars , addChars
   , changeChars
-  , yiSplitAt
   ) where
 
 import           Control.Lens
@@ -37,10 +35,11 @@ import           Data.Monoid
 import qualified Data.HashMap.Strict as HashMap
 import qualified Data.Map as Map
 import           Data.Maybe
+import           Data.Rope.UTF16 ( Rope )
+import qualified Data.Rope.UTF16 as Rope
 import qualified Language.Haskell.LSP.Types           as J
 import qualified Language.Haskell.LSP.Types.Lens      as J
 import           Language.Haskell.LSP.Utility
-import qualified Yi.Rope as Yi
 
 -- ---------------------------------------------------------------------
 {-# ANN module ("hlint: ignore Eta reduce" :: String) #-}
@@ -50,7 +49,7 @@ import qualified Yi.Rope as Yi
 data VirtualFile =
   VirtualFile {
       _version :: Int
-    , _text    :: Yi.YiString
+    , _text    :: Rope
     } deriving (Show)
 
 type VFS = Map.Map J.Uri VirtualFile
@@ -61,7 +60,7 @@ openVFS :: VFS -> J.DidOpenTextDocumentNotification -> IO VFS
 openVFS vfs (J.NotificationMessage _ _ params) = do
   let J.DidOpenTextDocumentParams
          (J.TextDocumentItem uri _ version text) = params
-  return $ Map.insert uri (VirtualFile version (Yi.fromText text)) vfs
+  return $ Map.insert uri (VirtualFile version (Rope.fromText text)) vfs
 
 -- ---------------------------------------------------------------------
 
@@ -132,87 +131,33 @@ data TextDocumentContentChangeEvent =
 -- | Apply the list of changes.
 -- Changes should be applied in the order that they are
 -- received from the client.
-applyChanges :: Yi.YiString -> [J.TextDocumentContentChangeEvent] -> Yi.YiString
+applyChanges :: Rope -> [J.TextDocumentContentChangeEvent] -> Rope
 applyChanges = foldl' applyChange
 
 -- ---------------------------------------------------------------------
 
-applyChange :: Yi.YiString -> J.TextDocumentContentChangeEvent -> Yi.YiString
+applyChange :: Rope -> J.TextDocumentContentChangeEvent -> Rope
 applyChange _ (J.TextDocumentContentChangeEvent Nothing Nothing str)
-  = Yi.fromText str
-applyChange str (J.TextDocumentContentChangeEvent (Just (J.Range fm _to)) (Just len) txt) =
-  if txt == ""
-    then -- delete len chars from fm
-      deleteChars str fm len
-    else -- add or change, based on length
-      if len == 0
-        then addChars str fm txt
-             -- Note: changeChars comes from applyEdit, emacs will split it into a
-             -- delete and an add
-        else changeChars str fm len txt
-applyChange str (J.TextDocumentContentChangeEvent (Just r@(J.Range (J.Position sl sc) (J.Position el ec))) Nothing txt)
-  = applyChange str (J.TextDocumentContentChangeEvent (Just r) (Just len) txt)
-    where len = Yi.length region
-          (beforeEnd, afterEnd) = Yi.splitAtLine el str
-          lastLine = Yi.take ec afterEnd
-          lastLine' | sl == el = Yi.drop sc lastLine
-                    | otherwise = lastLine
-          (_beforeStart, afterStartBeforeEnd) = Yi.splitAtLine sl beforeEnd
-          region = Yi.drop sc afterStartBeforeEnd <> lastLine'
-applyChange str (J.TextDocumentContentChangeEvent Nothing (Just _) _txt)
-  = str
-
--- ---------------------------------------------------------------------
-
-deleteChars :: Yi.YiString -> J.Position -> Int -> Yi.YiString
-deleteChars str (J.Position l c) len = str'
+  = Rope.fromText str
+applyChange str (J.TextDocumentContentChangeEvent (Just (J.Range (J.Position sl sc) _to)) (Just len) txt)
+  = changeChars str start len txt
   where
-    (before,after) = Yi.splitAtLine l str
-    -- after contains the area we care about, starting with the selected line.
-    -- Due to LSP zero-based coordinates
-    beforeOnLine = Yi.take c after
-    after' = Yi.drop (c + len) after
-    str' = Yi.append before (Yi.append beforeOnLine after')
-
--- ---------------------------------------------------------------------
-
-addChars :: Yi.YiString -> J.Position -> Text -> Yi.YiString
-addChars str (J.Position l c) new = str'
+    start = Rope.rowColumnCodeUnits (Rope.RowColumn sl sc) str
+applyChange str (J.TextDocumentContentChangeEvent (Just (J.Range (J.Position sl sc) (J.Position el ec))) Nothing txt)
+  = changeChars str start len txt
   where
-    (before,after) = Yi.splitAtLine l str
-    -- after contains the area we care about, starting with the selected line.
-    -- Due to LSP zero-based coordinates
-    beforeOnLine = Yi.take c after
-    after' = Yi.drop c after
-    str' = Yi.concat [before, beforeOnLine, (Yi.fromText new), after']
-
--- ---------------------------------------------------------------------
-
-changeChars :: Yi.YiString -> J.Position -> Int -> Text -> Yi.YiString
-changeChars str (J.Position ls cs) len new = str'
-  where
-    (before,after) = yiSplitAt ls cs str
-    after' = Yi.drop len after
-
-    str' = Yi.concat [before, (Yi.fromText new), after']
-
--- changeChars :: Yi.YiString -> J.Position -> J.Position -> String -> Yi.YiString
--- changeChars str (J.Position ls cs) (J.Position le ce) new = str'
---   where
---     (before,_after) = yiSplitAt ls cs str
---     (_before,after) = yiSplitAt le ce str
-
---     str' = Yi.concat [before, (Yi.fromString new), after]
---     -- str' = Yi.concat [before]
---     -- str' = Yi.concat [_before]
+    start = Rope.rowColumnCodeUnits (Rope.RowColumn sl sc) str
+    end = Rope.rowColumnCodeUnits (Rope.RowColumn el ec) str
+    len = end - start
+applyChange str (J.TextDocumentContentChangeEvent Nothing (Just _) _txt)
+  = str
 
 -- ---------------------------------------------------------------------
 
-yiSplitAt :: Int -> Int -> Yi.YiString -> (Yi.YiString, Yi.YiString)
-yiSplitAt l c str = (before,after)
+changeChars :: Rope -> Int -> Int -> Text -> Rope
+changeChars str start len new = mconcat [before, Rope.fromText new, after']
   where
-    (b,a) = Yi.splitAtLine l str
-    before = Yi.concat [b,Yi.take c a]
-    after = Yi.drop c a
+    (before, after) = Rope.splitAt start str
+    after' = Rope.drop len after
 
 -- ---------------------------------------------------------------------
diff --git a/stack-8.0.2.yaml b/stack-8.0.2.yaml
index ef09a9610..71c53945c 100644
--- a/stack-8.0.2.yaml
+++ b/stack-8.0.2.yaml
@@ -6,6 +6,7 @@ packages:
 extra-deps:
 - sorted-list-0.2.1.0
 - aeson-1.2.4.0
+- rope-utf16-splay-0.2.0.0
 flags: {}
 extra-package-dbs: []
 nix:
diff --git a/stack-8.2.2.yaml b/stack-8.2.2.yaml
index b521363b5..f7dac0343 100644
--- a/stack-8.2.2.yaml
+++ b/stack-8.2.2.yaml
@@ -5,6 +5,7 @@ packages:
 - ./haskell-lsp-types
 extra-deps:
 - sorted-list-0.2.1.0
+- rope-utf16-splay-0.2.0.0
 flags: {}
 extra-package-dbs: []
 nix:
diff --git a/stack-8.4.2.yaml b/stack-8.4.2.yaml
index 36fc642b5..270a2bdd1 100644
--- a/stack-8.4.2.yaml
+++ b/stack-8.4.2.yaml
@@ -5,7 +5,7 @@ packages:
 - ./haskell-lsp-types
 
 extra-deps:
-- yi-rope-0.11
+- rope-utf16-splay-0.2.0.0
 
 flags: {}
 extra-package-dbs: []
diff --git a/stack-8.4.3.yaml b/stack-8.4.3.yaml
index 1ced430fa..9b6ff1b98 100644
--- a/stack-8.4.3.yaml
+++ b/stack-8.4.3.yaml
@@ -5,6 +5,7 @@ packages:
 - ./haskell-lsp-types
 
 extra-deps:
+- rope-utf16-splay-0.2.0.0
 
 flags: {}
 extra-package-dbs: []
diff --git a/stack-8.6.1.yaml b/stack-8.6.1.yaml
index 1451525b9..b5c34fa14 100644
--- a/stack-8.6.1.yaml
+++ b/stack-8.6.1.yaml
@@ -5,6 +5,7 @@ packages:
 - ./haskell-lsp-types
 
 extra-deps:
+- rope-utf16-splay-0.2.0.0
 
 flags: {}
 extra-package-dbs: []
diff --git a/stack-8.6.3.yaml b/stack-8.6.3.yaml
index 6aa276dcf..f04ff7526 100644
--- a/stack-8.6.3.yaml
+++ b/stack-8.6.3.yaml
@@ -5,6 +5,7 @@ packages:
 - ./haskell-lsp-types
 
 extra-deps:
+- rope-utf16-splay-0.2.0.0
 
 flags: {}
 extra-package-dbs: []
diff --git a/test/VspSpec.hs b/test/VspSpec.hs
index 56225e784..7755cd29b 100644
--- a/test/VspSpec.hs
+++ b/test/VspSpec.hs
@@ -2,9 +2,10 @@
 module VspSpec where
 
 
+import           Data.String
+import qualified Data.Rope.UTF16 as Rope
 import           Language.Haskell.LSP.VFS
 import qualified Language.Haskell.LSP.Types as J
-import qualified Yi.Rope as Yi
 
 import           Test.Hspec
 
@@ -62,9 +63,9 @@ vspSpec = do
           , "-- fooo"
           , "foo :: Int"
           ]
-        new = applyChange (Yi.fromString orig)
+        new = applyChange (fromString orig)
                 $ J.TextDocumentContentChangeEvent (mkRange 2 1 2 5) (Just 4) ""
-      lines (Yi.toString new) `shouldBe`
+      lines (Rope.toString new) `shouldBe`
           [ "abcdg"
           , "module Foo where"
           , "-oo"
@@ -79,9 +80,9 @@ vspSpec = do
           , "-- fooo"
           , "foo :: Int"
           ]
-        new = applyChange (Yi.fromString orig)
+        new = applyChange (fromString orig)
                 $ J.TextDocumentContentChangeEvent (mkRange 2 1 2 5) Nothing ""
-      lines (Yi.toString new) `shouldBe`
+      lines (Rope.toString new) `shouldBe`
           [ "abcdg"
           , "module Foo where"
           , "-oo"
@@ -99,9 +100,9 @@ vspSpec = do
           , "-- fooo"
           , "foo :: Int"
           ]
-        new = applyChange (Yi.fromString orig)
+        new = applyChange (fromString orig)
                 $ J.TextDocumentContentChangeEvent (mkRange 2 0 3 0) (Just 8) ""
-      lines (Yi.toString new) `shouldBe`
+      lines (Rope.toString new) `shouldBe`
           [ "abcdg"
           , "module Foo where"
           , "foo :: Int"
@@ -116,9 +117,9 @@ vspSpec = do
           , "-- fooo"
           , "foo :: Int"
           ]
-        new = applyChange (Yi.fromString orig)
+        new = applyChange (fromString orig)
                 $ J.TextDocumentContentChangeEvent (mkRange 2 0 3 0) Nothing ""
-      lines (Yi.toString new) `shouldBe`
+      lines (Rope.toString new) `shouldBe`
           [ "abcdg"
           , "module Foo where"
           , "foo :: Int"
@@ -134,9 +135,9 @@ vspSpec = do
           , "foo :: Int"
           , "foo = bb"
           ]
-        new = applyChange (Yi.fromString orig)
+        new = applyChange (fromString orig)
                 $ J.TextDocumentContentChangeEvent (mkRange 1 0 3 0) (Just 19) ""
-      lines (Yi.toString new) `shouldBe`
+      lines (Rope.toString new) `shouldBe`
           [ "module Foo where"
           , "foo = bb"
           ]
@@ -150,9 +151,9 @@ vspSpec = do
           , "foo :: Int"
           , "foo = bb"
           ]
-        new = applyChange (Yi.fromString orig)
+        new = applyChange (fromString orig)
                 $ J.TextDocumentContentChangeEvent (mkRange 1 0 3 0) Nothing ""
-      lines (Yi.toString new) `shouldBe`
+      lines (Rope.toString new) `shouldBe`
           [ "module Foo where"
           , "foo = bb"
           ]
@@ -167,8 +168,9 @@ vspSpec = do
           , "module Foo where"
           , "foo :: Int"
           ]
-        new = addChars (Yi.fromString orig) (J.Position 1 16) "\n-- fooo"
-      lines (Yi.toString new) `shouldBe`
+        new = applyChange (fromString orig)
+                $ J.TextDocumentContentChangeEvent (mkRange 1 16 1 16) (Just 0) "\n-- fooo"
+      lines (Rope.toString new) `shouldBe`
           [ "abcdg"
           , "module Foo where"
           , "-- fooo"
@@ -184,8 +186,9 @@ vspSpec = do
           [ "module Foo where"
           , "foo = bb"
           ]
-        new = addChars (Yi.fromString orig) (J.Position 1 8) "\n-- fooo\nfoo :: Int"
-      lines (Yi.toString new) `shouldBe`
+        new = applyChange (fromString orig)
+                $ J.TextDocumentContentChangeEvent (mkRange 1 8 1 8) Nothing "\n-- fooo\nfoo :: Int"
+      lines (Rope.toString new) `shouldBe`
           [ "module Foo where"
           , "foo = bb"
           , "-- fooo"
@@ -209,10 +212,10 @@ vspSpec = do
           , "baz = do"
           , "  putStrLn \"hello world\""
           ]
-        -- new = changeChars (Yi.fromString orig) (J.Position 7 0) (J.Position 7 8) "baz ="
-        new = applyChange (Yi.fromString orig)
+        -- new = changeChars (fromString orig) (J.Position 7 0) (J.Position 7 8) "baz ="
+        new = applyChange (fromString orig)
                 $ J.TextDocumentContentChangeEvent (mkRange 7 0 7 8) (Just 8) "baz ="
-      lines (Yi.toString new) `shouldBe`
+      lines (Rope.toString new) `shouldBe`
           [ "module Foo where"
           , "-- fooo"
           , "foo :: Int"
@@ -237,10 +240,10 @@ vspSpec = do
           , "baz = do"
           , "  putStrLn \"hello world\""
           ]
-        -- new = changeChars (Yi.fromString orig) (J.Position 7 0) (J.Position 7 8) "baz ="
-        new = applyChange (Yi.fromString orig)
+        -- new = changeChars (fromString orig) (J.Position 7 0) (J.Position 7 8) "baz ="
+        new = applyChange (fromString orig)
                 $ J.TextDocumentContentChangeEvent (mkRange 7 0 7 8) Nothing "baz ="
-      lines (Yi.toString new) `shouldBe`
+      lines (Rope.toString new) `shouldBe`
           [ "module Foo where"
           , "-- fooo"
           , "foo :: Int"
@@ -251,3 +254,15 @@ vspSpec = do
           , "baz ="
           , "  putStrLn \"hello world\""
           ]
+    it "indexes using utf-16 code units" $ do
+      let
+        orig = unlines
+          [ "a𐐀b"
+          , "a𐐀b"
+          ]
+        new = applyChange (fromString orig)
+                $ J.TextDocumentContentChangeEvent (mkRange 1 0 1 3) (Just 3) "𐐀𐐀"
+      lines (Rope.toString new) `shouldBe`
+          [ "a𐐀b"
+          , "𐐀𐐀b"
+          ]