diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -228,3 +228,7 @@
 ## 0.24.2.0 -- 2020-04-06
 
 * Twenty-fourth version revised B. Fixed issue with overwritten "result.wav" file in some functions. Now the program works as expected for these functions. Some minor documentation improvements. 
+
+## 0.24.3.0 -- 2020-04-06
+
+* Twenty-fourth version revised C. Fixed issue with being not compiled code because of the wrong type signature. 
diff --git a/DobutokO/Sound/Functional.hs b/DobutokO/Sound/Functional.hs
--- a/DobutokO/Sound/Functional.hs
+++ b/DobutokO/Sound/Functional.hs
@@ -247,8 +247,8 @@
 
 -- | Combines (mixes) all \"test\*" files in the given directory. The files should be similar in parameters and must be sound files for SoX to work
 -- on them properly. Afterwards, the function deletes these combined files.
-mixTest :: Int -> Int -> IO ()
-mixTest zeroN j = do
+mixTest :: IO ()
+mixTest = do
   paths0 <- listDirectory "."
   let paths = sort . filter (isPrefixOf "test") $ paths0
   _ <- readProcessWithExitCode (fromJust (showE "sox")) (["--combine", "mix"] ++ paths ++ ["result.wav","vol","0.3"]) ""
@@ -256,8 +256,8 @@
 
 -- | Similar to 'mixTest', but allows to change the sound quality parameters for the resulting file. For more information, please, refer to
 -- 'soxBasicParams'.
-mixTest2G :: Int -> Int -> String -> IO ()
-mixTest2G zeroN j ys = do
+mixTest2G :: String -> IO ()
+mixTest2G ys = do
   paths0 <- listDirectory "."
   let paths = sort . filter (isPrefixOf "test") $ paths0
   _ <- readProcessWithExitCode (fromJust (showE "sox")) (["--combine", "mix"] ++ paths ++ soxBasicParams ys ["result.wav","vol","0.3"]) ""
diff --git a/dobutokO2.cabal b/dobutokO2.cabal
--- a/dobutokO2.cabal
+++ b/dobutokO2.cabal
@@ -2,7 +2,7 @@
 -- documentation, see http://haskell.org/cabal/users-guide/
 
 name:                dobutokO2
-version:             0.24.2.0
+version:             0.24.3.0
 synopsis:            A program and a library to create experimental music from a mono audio and a Ukrainian text
 description:         It can also create a timbre for the notes. Uses SoX inside.
 homepage:            https://hackage.haskell.org/package/dobutokO2