diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -115,3 +115,8 @@
 ## 0.6.3.1 -- 2020-02-23
 
 * Sixth version revised D. Fixed an issue with word usage (a terminology) in the documentation for 'genControl' function.
+
+## 0.6.4.0 -- 2020-05-11
+
+* Sixth version revised E. Changed sound representations for the Ukrainian "и" -- file "K.wav", "к" -- file "M.wav", "т" -- file "V.wav", "ч" -- file "b.wav", 
+"і" -- file "e.wav".
diff --git a/K.wav b/K.wav
Binary files a/K.wav and b/K.wav differ
diff --git a/M.wav b/M.wav
Binary files a/M.wav and b/M.wav differ
diff --git a/V.wav b/V.wav
Binary files a/V.wav and b/V.wav differ
diff --git a/b.wav b/b.wav
Binary files a/b.wav and b/b.wav differ
diff --git a/e.wav b/e.wav
Binary files a/e.wav and b/e.wav differ
diff --git a/mmsyn6ukr.cabal b/mmsyn6ukr.cabal
--- a/mmsyn6ukr.cabal
+++ b/mmsyn6ukr.cabal
@@ -2,7 +2,7 @@
 -- documentation, see http://haskell.org/cabal/users-guide/
 
 name:                mmsyn6ukr
-version:             0.6.3.1
+version:             0.6.4.0
 synopsis:            A musical instrument synthesizer or a tool for Ukrainian language listening
 description:         A program can be used as a musical instrument synthesizer or for Ukrainian speech synthesis especially for poets and writers
 homepage:            https://hackage.haskell.org/package/mmsyn6ukr