This message occurs when you launch the holidays explorer, if any of the recurring holidays in your shared database needs to be re-generated.
Depending on what you want to do in the Holidays Explorer, the modified holidays may not affect you, but if they do then the holidays displayed in the holidays explorer could be wrong (different from the latest rules that you saved) if you click no.
You really should address this message before you send the exported data for proof-reading.
Topic 174955, last updated on 16-May-2024