diff --git a/build.xml b/build.xml
index 92c234df2..87d3fa3ba 100644
--- a/build.xml
+++ b/build.xml
@@ -1468,13 +1468,11 @@ BOOTRAPING TEST AND TEST SUITE
 ============================================================================ -->
 
   <target name="test.stability" depends="strap.done">
-<!-- commented out for now.
-    <same dir="${build-quick.dir}" todir="${build-strap.dir}" failondifferent="yes">
+    <same dir="${build-quick.dir}" todir="${build-strap.dir}" failondifferent="no">
       <exclude name="**/*.properties"/>
       <exclude name="bin/**"/>
       <exclude name="*.complete"/>
     </same>
--->
   </target>
 
   <target name="test.run" depends="pack.done">
diff --git a/src/compiler/scala/tools/nsc/symtab/classfile/UnPickler.scala b/src/compiler/scala/tools/nsc/symtab/classfile/UnPickler.scala
index 2a03c1a33..d87b22811 100644
--- a/src/compiler/scala/tools/nsc/symtab/classfile/UnPickler.scala
+++ b/src/compiler/scala/tools/nsc/symtab/classfile/UnPickler.scala
@@ -68,10 +68,21 @@ abstract class UnPickler {
     private def checkVersion(filename: String) {
       val major = readNat()
       val minor = readNat()
+
+// remove the portion below, between "cut here", before releasing the first 2.8 beta
+
 //---cut here---
+
+      // transiently, use this bit as long as stability fails.
+      if (major != 4 && major != 5)
+
+      // once stability is restored, use the following bit instead:
+/*
       if (major == 4) { // !!! temporarily accept 4 as version. 
         println("WARNING: old class format, please recompile "+filename)
       } else
+*/
+
 //---cut here---
       if (major != MajorVersion || minor > MinorVersion)
         throw new IOException("Scala signature " + classRoot.name +