Hi Paolo,

Yes, the error is quite strange it seems that the updated value of a field, a date/time I suppose, ends up in a position that is interpreted as an Item name.

As a rule of thumb newer Lightstreamer servers usually support older clients; this allows our customers to go live in production with the new server version and old clients, and then upgrade the clients at their convenience.
So, I expect that your old clients should work fine with the 6.0.3 server without any changes.
Please could you check if the client page used with the new server is exactly the same that the old one? Checking the server log file could you confirm that the application data of the updates are exactly the same between server 5 and server 6?

Regards,
Giuseppe