a newer html client library is not officially compatible with an older server but may partially work; see the changelog for the details: http://www.lightstreamer.com/share/C...TML#web_client

Please note that we always advise to upgrade the server first (newer servers are always compatible with older client libraries) and then the client.

In any case, did you had the evidence that the problem is with the client library? An upgrade may not solve your issue if such issue is somewhere else