Hi,
I have replied to the support case, however for the benefit of others - new fields will get automatically created in any current stream in the event database, however they will be created with their UDO variable name, rather than a more friendly alias.
There is also a buffer to the database of up to an hour, or 10Mb of data, depending on which happens first, so changes during that time may not be seen.
Connecting data systems since the 1980s.