diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -45,3 +45,7 @@
 
 * Eigth version. Changed the module structure. Removed the module DobutokO.Poetry.PrependAppend and added the module DobutokO.Poetry.General with more extended 
 possibilities. Addad also README.md file with some useful information. Some code and documentation improvements.
+
+## 0.8.1.0 -- 2020-07-31
+
+* Eigth version revised A. Fixed issue with being not compiled fo GHC versions prior to 8.4* series. 
diff --git a/DobutokO/Poetry/StrictV.hs b/DobutokO/Poetry/StrictV.hs
--- a/DobutokO/Poetry/StrictV.hs
+++ b/DobutokO/Poetry/StrictV.hs
@@ -14,9 +14,9 @@
 module DobutokO.Poetry.StrictV where
 
 #ifdef __GLASGOW_HASKELL__
-#if __GLASGOW_HASKELL__>=710
-/* code that applies only to GHC 7.10.* and higher versions */
-import GHC.Base ((<>))
+#if __GLASGOW_HASKELL__>=804
+/* code that applies only to GHC 8.4.* and higher versions */
+import Data.Semigroup ((<>))
 import Prelude hiding ((<>))
 #endif
 #endif
@@ -47,12 +47,12 @@
 
 preAppend :: [a] -> [[a]] -> [[a]] -> [[a]]
 #ifdef __GLASGOW_HASKELL__
-#if __GLASGOW_HASKELL__>=710
+#if __GLASGOW_HASKELL__>=804
 preAppend ts !uss tss = ts:tss <> uss
 #endif
 #endif
 #ifdef __GLASGOW_HASKELL__
-#if __GLASGOW_HASKELL__==708
+#if __GLASGOW_HASKELL__<804
 preAppend ts !uss tss = ts:tss ++ uss
 #endif
 #endif
diff --git a/dobutokO-poetry.cabal b/dobutokO-poetry.cabal
--- a/dobutokO-poetry.cabal
+++ b/dobutokO-poetry.cabal
@@ -2,7 +2,7 @@
 -- documentation, see http://haskell.org/cabal/users-guide/
 
 name:                dobutokO-poetry
-version:             0.8.0.0
+version:             0.8.1.0
 synopsis:            Helps to order the 7 or less Ukrainian words to obtain somewhat suitable for poetry or music text
 description:         Helps to order the 7 or less Ukrainian words (or their concatenations) to obtain somewhat suitable for poetry or music text. Can be also used as a research instrument with generalized functions.
 
@@ -27,8 +27,8 @@
 
 executable dobutokO-poetry
   main-is:             Main.hs
-  other-modules:       DobutokO.Poetry.Basic, DobutokO.Poetry, DobutokO.Poetry.StrictV, DobutokO.Poetry.Auxiliary, DobutokO.Poetry.Norms, DobutokO.Poetry.UniquenessPeriodsG
-  other-extensions:    BangPatterns, CPP
+  other-modules:       DobutokO.Poetry.Basic, DobutokO.Poetry, DobutokO.Poetry.StrictV, DobutokO.Poetry.Auxiliary, DobutokO.Poetry.Norms, DobutokO.Poetry.UniquenessPeriodsG, DobutokO.Poetry.General
+  other-extensions:    BangPatterns, CPP, FlexibleInstances, MultiParamTypeClasses
   build-depends:       base >=4.7 && <4.15, vector >=0.11 && <0.14, mmsyn3 >=0.1.5 && <1, mmsyn7s >=0.6.7 && <1, mmsyn6ukr >=0.7.3 && <1
   -- hs-source-dirs:
   default-language:    Haskell2010