URL:
https://github.com/bitcoin/bitcoin/pull/150Add 'settxfee' RPC, to change TX fee setting at runtime
This clamps TX fee, if not zero, between "network minimum" (0.01) and 5 BTC (IMO sanity limit).
Presumably, the "network minimum" might be lowered, as is occasionally discussed on IRC and forum. This RPC prevents setting TX fee below network minimum.