I have requested that and other similar configuration features via our internal feature request system some time ago but it is not currently on the R&D road map. It may be something to look for in 2020 after the remaining gap features have been completed later this year.
The 30 day record keeping/logging is committed to the PG database programmatically. Further, I could not find an NP system config file or setting to allow for expanding the number of days beyond 30 days unfortunately either.
I'll post a comment here if this changes in the coming year.
We are just 'like' you & like to be 'liked' when we provide a helpful answer and when you press the 'Solution Accepted' button if an answer provided resolves your question or issue 🙂 Cheers!