This would also solve CSV should have property column but basically it would make sense that the CSV format for uploading transactions should match the format that you download when you export transactions. This includes columns such as Sub Category, Property, Portfolio etc.
Additionally I’d consider the ability to include the transaction ID in the CSV. That way if I download all transactions for a year, find errors and make changes, I don’t have to delete the entire year from Stessa in order to re-upload. The upload would match transaction ids and update those rows instead of appending to the end of the table. I do realize this could be potentially dangerous to have on by default as you could end up with duplicate IDs or unintentional overwrites if A) the upload system didn’t check for duplicates first or B) the user didn’t understand data entry and how a table works.