diff --git a/build.cmd b/build.cmd
index 806e875..c3cff58 100644
--- a/build.cmd
+++ b/build.cmd
@@ -1,8 +1,16 @@
-dotnet pack src/CallPolly --configuration Release -o "%CD%\bin" --version-suffix CI%1
+SETLOCAL
+SET X=%1
+SET BLD=000000%X%
+SET BLD=%BLD:~-7%
+if [%2]==[] (SET V=CI%BLD%) else (SET V=pr%2-%BLD%)
+
+dotnet pack src/CallPolly --configuration Release -o "%CD%\bin" --version-suffix %V%
 if ERRORLEVEL 1 (echo Error building CallPolly; exit /b 1)
 
 dotnet test tests/CallPolly.Tests --configuration Release
 if ERRORLEVEL 1 (echo Error testing CallPolly; exit /b 1)
 
 dotnet test tests/CallPolly.Acceptance --configuration Release
-if ERRORLEVEL 1 (echo Error acceptance testing CallPolly; exit /b 1)
\ No newline at end of file
+if ERRORLEVEL 1 (echo Error acceptance testing CallPolly; exit /b 1)
+
+ENDLOCAL