(note: this is a temporary file, to be added-to by anybody, and moved to release-notes at release time)
Transaction fee changes
This release automatically estimates how high a transaction fee (or how high a priority) transactions require to be confirmed quickly. The default settings will create transactions that confirm quickly; see the new 'txconfirmtarget' setting to control the tradeoff between fees and confirmation times.
Prior releases used hard-coded fees (and priorities), and would sometimes create transactions that took a very long time to confirm.
New Command Line Options
-txconfirmtarget=n : create transactions that have enough fees (or priority) so they are likely to confirm within n blocks (default: 1). This setting is over-ridden by the -paytxfee option.
New RPC methods
estimatefee nblocks : Returns approximate fee-per-1,000-bytes needed for a transaction to be confirmed within nblocks. Returns -1 if not enough transactions have been observed to compute a good estimate.
estimatepriority nblocks : Returns approximate priority needed for a zero-fee transaction to confirm within nblocks. Returns -1 if not enough free transactions have been observed to compute a good estimate.
Statistics used to estimate fees and priorities are saved in the data directory in the 'fee_estimates.dat' file just before program shutdown, and are read in at startup.