I've just discovered that IB allows accessing Flex Queries via a fairly simple HTTP API: https://www.interactivebrokers.com/campus/ibkr-api-page/flex-web-service/

I think it would be possible to use this to implement automatic transaction updates from IB. It could work similarly to how exchange rate fetchers work:

• In config, add query ID and secret token
• PP periodically fetches transactions, at most once a day

Open questions:

• The max. duration for a single export is 365 days. There would need to be some place to store / retrieve the last fetch date.
• The secret token expires after max one year. There would need to be a UI to surface this to the user.