When downloading OFX statement files for an account, the FITID field is not valid as it does not adhere to the OFX standard. The FITID field should remain the same for each time that a transaction is downloaded. Example: I download a statement on 10 September 2018 for last 30 days. Your current implementation will assign the FITID upon the OFX file being generated in this manner: <FITID> 201808127 Lets break this down: 20180812 = date of transaction as per statement 7 = your starting digit for the first transaction for this statement download, this number is then incremented for every transaction on the statement. Now if I download a statement for last 60 days, then the FITID above is generated again but for the first transaction on the statement which is 60 days ago. This means that the FITID number is not assigned to a single transaction, but rather just generated when the OFX file is generated and does not uniquely identify any transactions on the statement across statements that overlap on date ranges. To summarize: If I download both a 60 and 30 day OFX statement, the FITID numbers do not identify the same transaction across the statements. This occurs even if you download a 30 day statement today, and another tomorrow with additional transactions.
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