diff --git a/mlsource/MLCompiler/CompilerVersion.sml b/mlsource/MLCompiler/CompilerVersion.sml
index 7ce8f68c..7598f1b2 100644
--- a/mlsource/MLCompiler/CompilerVersion.sml
+++ b/mlsource/MLCompiler/CompilerVersion.sml
@@ -1,23 +1,23 @@
 (*
     Copyright (c) 2007-19 David C.J. Matthews
 
     This library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Lesser General Public
     License version 2.1 as published by the Free Software Foundation.
     
     This library is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     Lesser General Public License for more details.
     
     You should have received a copy of the GNU Lesser General Public
     License along with this library; if not, write to the Free Software
     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *)
 
 structure CompilerVersion =
 struct
-   val compilerVersion = "5.8 Release"
-   val versionNumber = 580
+   val compilerVersion = "5.8.1 Testing"
+   val versionNumber = 581
    val versionSuffix = Int.toString versionNumber
 end;