diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -3,3 +3,7 @@
 ## 0.1.0.0 -- YYYY-mm-dd
 
 * First version. Released on an unsuspecting world.
+
+## 0.1.1.0 -- 2019-10-18
+
+* First version revised A. Changed usage of errors to Maybe inside IO monad.
diff --git a/EndOfExe.hs b/EndOfExe.hs
--- a/EndOfExe.hs
+++ b/EndOfExe.hs
@@ -4,19 +4,23 @@
 import Data.Maybe (isJust)
 import System.IO.Unsafe (unsafePerformIO)
 
--- | Function that is used instead of System.Info.os to check whether the executable ends in .exe
-endOfExecutable :: String -> IO String                              
+-- | Function that is used instead of System.Info.os to check whether the executable ends in .exe. The function returns IO Nothing if there is neither ys nor (ys ++ ".exe") names for executables in the 
+-- variable PATH
+endOfExecutable :: String -> IO (Maybe String)
 endOfExecutable ys = do
                        xs <- D.findExecutable ys
                        if isJust xs 
-                         then return ""
+                         then return $ fmap (ys ++) (Just "")
                          else do
                                 zs <- D.findExecutable (ys ++ ".exe")
                                 if isJust zs
-                                  then return ".exe"
+                                  then return $ fmap (ys ++) (Just ".exe")
                                   else error ("Please, install the executable " ++ ys ++ " into the directory in the PATH variable!")
                                   
 -- | Function that is used to concat the endOfExecutable to the name of the program. You can use showE \"nameOfExecutable\" e. g. inside the System.Process.callCommand as the name of the executable
-showE :: String -> String
-showE xs | null xs = []
-         | otherwise = xs ++ unsafePerformIO (endOfExecutable xs)
+showE :: String -> Maybe String
+showE xs | null xs = error "No executable specified!"
+         | otherwise = let r = unsafePerformIO . endOfExecutable $ xs in 
+            if isJust r
+              then r
+              else Nothing
diff --git a/mmsyn3.cabal b/mmsyn3.cabal
--- a/mmsyn3.cabal
+++ b/mmsyn3.cabal
@@ -2,9 +2,9 @@
 -- documentation, see http://haskell.org/cabal/users-guide/
 
 name:                mmsyn3
-version:             0.1.0.0
+version:             0.1.1.0
 synopsis:            A small library to deal with executable endings
--- description:
+description:         A small library to deal with executable endings. Uses a Maybe data representation inside an IO monad.
 homepage:            http://hackage.haskell.org/package/mmsyn3
 license:             MIT
 license-file:        LICENSE