Snapshot of the data can be saved at any time from your list of participants, your rooming lists, etc. Later you can print the differences between the current data and one of the old data snapshots.
How to proceed?
Activate the data snapshot module in preferences > modules > event tab and submit your modification.
Once this module is enabled, on top of the most relevant lists there will be an additional snapshot icon .
Click on this snapshot icon to get the list of snapshot from this list.
The first time you access a list, it will be empty! Save a snapshot by clicking on the top right "+", give this snapshot a name for your records ans submit.
You have now a data snapshot in your list. Select it and you can either download it in Excel format or list the differences between the data snapshot and the current data. If you do it immediately, there will be no differences.
Later to view the differences with your data snapshot, return to the list, click on the snapshot icon , select one of the data snapshot and "diff". A list of the modified rows will be printed. The row from the data snapshot highlighted in grey, followed by the row from the current data highlighted in green. The modified cells will be highlighted in light pink in the current data row.