I discovered a critical systemic problem with Zoho Books, confirmed by Zoho developers, which has not been made public and needs to be addressed immediately. At the very least, a warning should be issued.

The locking mechanism for data does not work in all cases, so we can say it is non-functioning, and it does not provide accounting data records security.

If you update inventory values and volumes, a common practice with year end recordings, and use the bulk update, which is necessary when dealing with hundreds of items, there will be no warning for impacts on COGS from the previous fiscal year. This then changes the COGS and the retained earnings figures, likely reported to your tax authorities.
Because we were bulk updating, it was impossible to find out exactly where the problem occurred, and now we don't have unified data. At this point, all we could do is make a manual journal for the start of the next fiscal year. Would love to know of another solution.