<p>I am wondering whether it is safe to mix jdk 1.5 and 1.6 (Java 6) object serialization (biderctional communication). I searched for an explicit statement from sun concerning this question but did not succeed. So, besides the technical feasability I am searching for an "official" statement concerning the problem.</p>

After testing with a serialized object written to a file using the ObjectOutputStream in a Java 1.5 program, then running a read with a ObjectInputStream in a Java 1.6 program I can say this worked without any issue.