* improve robustness and performance of uTP PMTU discovery
* fix duplicate ACK issue in uTP
* support filtering which parts of session state are loaded by load_state()
* deprecate support for adding torrents by HTTP URL
* allow specifying which tracker to scrape in scrape_tracker
* tracker response alerts from user initiated announces/scrapes are now
posted regardless of alert mask
* improve DHT performance when changing external IP (primarily affects
bootstrapping).
* add feature to stop torrents immediately after checking files is done
* make all non-auto managed torrents exempt from queuing logic, including
checking torrents.
* add option to not proxy tracker connections through proxy
* removed sparse-regions feature
* support using 0 disk threads (to perform disk I/O in network thread)
* removed deprecated handle_alert template
* enable logging build config by default (but alert mask disabled by default)
* deprecated RSS API
* experimental support for BEP 38, "mutable torrents"
* replaced lazy_bdecode with a new bdecoder that's a lot more efficient
* deprecate time functions, expose typedefs of boost::chrono in the
libtorrent namespace instead
* deprecate file_base feature in file_storage/torrent_info
* changed default piece and file priority to 4 (previously 1)
* improve piece picker support for reverse picking (used for snubbed peers)
to not cause priority inversion for regular peers
* improve piece picker to better support torrents with very large pieces
and web seeds. (request large contiguous ranges, but not necessarily a
whole piece).
* deprecated session_status and session::status() in favor of performance
counters.
* improve support for HTTP where one direction of the socket is shut down.
* remove internal fields from web_seed_entry
* separate crypto library configuration <crypto> and whether to support
bittorrent protocol encryption <encryption>
* simplify bittorrent protocol encryption by just using internal RC4
implementation.
* optimize copying torrent_info and file_storage objects
* cancel non-critical DNS lookups when shutting down, to cut down on
shutdown delay.
* greatly simplify the debug logging infrastructure. logs are now delivered
as alerts, and log level is controlled by the alert mask.
* removed auto_expand_choker. use rate_based_choker instead
* optimize UDP tracker packet handling
* support SSL over uTP connections
* support web seeds that resolve to multiple IPs
* added auto-sequential feature. download well-seeded torrents in-order
* removed built-in GeoIP support (this functionality is orthogonal to
libtorrent)
* deprecate proxy settings in favor of regular settings
* deprecate separate settings for peer protocol encryption
* support specifying listen interfaces and outgoing interfaces as device
names (eth0, en2, tun0 etc.)
* support for using purgrable memory as disk cache on Mac OS.
* be more aggressive in corking sockets, to coalesce messages into larger
packets.
* pre-emptively unchoke peers to save one round-trip at connection start-up.
* add session constructor overload that takes a settings_pack
* torrent_info is no longer an intrusive_ptr type. It is held by shared_ptr.
This is a non-backwards compatible change
* move listen interface and port to the settings
* move use_interfaces() to be a setting
* extend storage interface to allow deferred flushing and flush the part-file
metadata periodically
* make statistics propagate instantly rather than on the second tick
* support for partfiles, where partial pieces belonging to skipped files are
put
* support using multiple threads for socket operations (especially useful for
high performance SSL connections)
* allow setting rate limits for arbitrary peer groups. Generalizes
per-torrent rate limits, and local peer limits
* improved disk cache complexity O(1) instead of O(log(n))
* add feature to allow storing disk cache blocks in an mmapped file
(presumably on an SSD)
* optimize peer connection distribution logic across torrents to scale
better with many torrents
* replaced std::map with boost::unordered_map for torrent list, to scale
better with many torrents
* optimized piece picker
* optimized disk cache
* optimized .torrent file parsing
* optimized initialization of storage when adding a torrent
* added support for adding torrents asynchronously (for improved startup
performance)
* added support for asynchronous disk I/O
* almost completely changed the storage interface (for custom storage)
* added support for hashing pieces in multiple threads
* fix padfile issue
* fix PMTUd bug
* update puff to fix gzip crash