text: Joinmarket-clientserver 0.4.0:
  =================
  
  <https://github.com/joinmarket-org/joinmarket-clientserver/releases/tag/v0.4.0>
  
  This is a significant upgrade, but mostly to features `behind the scenes` that should improve both the
  security and the performance (in terms of coinjoin success/quality). However it is not a security critical
  release, nor includes any genuinely breaking changes. See the next section, Upgrade, for more details; there
  are a couple of minor things you should do when upgrading, but it shouldn't cause any real hassle.
  
  Please report bugs using the issue tracker at github:
  
  <https://github.com/joinmarket-org/joinmarket-clientserver/issues>
  
  Upgrading 
  =========
  
  To upgrade:
  
  First run the `install.sh` script as mentioned in the README. When prompted to overwrite the directory `jmvenv`, accept.
  
  Next: there is a small but not disruptive task to do: upgrade the wallet file format. Use the instructions
  [here](https://github.com/JoinMarket-Org/joinmarket-clientserver/blob/master/docs/wallet-upgrade.md) . Note this
  does not require doing transactions, or rescanning Core or anything similarly disruptive; it's purely a file format change (see
  "Notable Changes" (under "Upgrade of wallet ...") below for details on this wallet upgrade).
  Obviously do keep a backup of the previous format, at least initially, but the new format has been quite widely tested now
  and shouldn't cause issues in usage.
  
  Thirdly: this can be skipped for now if you don't have time, but: see
  [here](https://github.com/JoinMarket-Org/joinmarket-clientserver/blob/master/docs/config-irc-update.md)
  for how to change the format in the configuration
  for IRC servers. It's a trivial change that just helps out in situations where one of the IRC servers is down (you can now
  just comment it out, unlike before).
  
  Fourthly: (this can also be skipped until later) When running `sendpayment.py` or `tumbler.py` you will be prompted to choose
  a specific value for the maximum coinjoin fee(s) per participant, or accept a default random value. Details on the reason
  for this below in "Notable changes", under "Order chooser improvement"
  
  
  Notable changes
  ===============
  
  ### Upgrade of wallet code and wallet file format
  
  The wallet file has changed from a partially encrypted JSON format to a
  fully encrypted binary format (dubbed JMDAT). This hides some metadata
  previously accessable to anyone having access to the file itself, like
  the number and mixdepths of imported keys, how heavily a wallet has been
  used, or if it is a testnet or mainnet wallet.
  
  Additionally the password hashing algorithm has been upgraded from a
  weak double-iterated SHA-256 hash to Argon2, an algorithm specifically
  developed for hashing passwords. This change makes it much more costly
  to attack a wallet file with an unknown password.
  
  The encryption algorithm itself remains unchanged. It is still
  AES-256-CBC.
  
  Under the hood, the code for storing data on disk has been separated
  from the code working on the data. This abstraction reduces the code
  complexity and allows easier code review/verification.
  
  Other than that, the wallet code has been completely rewitten, with the
  intention of making it more robust, well-structured and universal. With
  the new code it will be much easier to abstract the joinmarket codebase
  away from specific bitcoin address versions (adding segwit support
  required a vast amount of code changes all over the place, in some cases
  causing problems with keeping it compatible with the previously used
  P2PKH addresses) and possibly even from bitcoin itself (however, there
  are no plans to support any other cryptocurrencies than bitcoin). This
  will especially be relevant when eventually adding support for native
  segwit coinjoins (bech32 addresses) in the future.
  
  a0c1d5a add upgrade notes
  
  8885e61 revert bad assert fix
  
  a929cf3 make log output human-readable again
  
  aa2c1d9 fix some bugs in wallet_utils
  
  9dd1dc7 fix wallet sync in fast mode
  
  98f41f7 make SimpleLruCache an actual LRU cache
  
  703ae04 remove wallet.sign()
  
  34f8600 fix wallet syncing
  
  747c227 fix some max_mixdepth off-by-one errors
  
  39e4276 change default wallet name
  
  8b9abef add is_segwit_mode() utility function
  
  8ca6cfc make sure new addresses always get imported
  
  914a40e adopt wallet_utils for new wallet
  
  cdbb345 remove uses of internal wallet data from electruminterface. NOTE: changes untested, probably breaks electruminterface somehow
  
  1f30967 adopt blockchaininterface for new wallet
  
  705d41d remove usages of wallet.unspent
  
  89b5cd4 add new wallet classes to existing tests
  
  3cf9926 remove references to old wallet classes
  
  2a0757c remove BitcoinCoreWallet
  
  6aaabb2 change yieldgenerator using new wallet implementation, start porting wallet_utils
  
  995c123 replace old wallet implementation with new one
  
  474a77d add setup.py dependencies
  
  ca57a14 add new wallet implementation
  
  455d092 minor bugfixes to Qt for new wallet code
  
  fd0e5b2 Merge #181: new wallet follow-up
  
  3a89ee4 move wallet upgrade docs and improve wallet opening error handling
  
  310fac8 add test for wallet.mixdepth
  
  3921882 change wallet mixdepth behaviour
  
  d3a6dd0 fix old wallet conversion with mnemonic extension
  
  6a26e48 Disallow less than 1 mixdepth in changemixdepth. Maxmixdepth error msg in tumbler: fix off-by-one
  
  fdd0d11 Remove --rpcwallet CLI option
  
  a65b822 fix help msg error for changemixdepth
  
  8f434b5 open wallet in read-only mode if possible
  
  697d8d7 bugfix: sendpayment invalid reference to userpcwallet
  
  ### Remove use of deprecated accounts feature in Core
  
  As of Bitcoin Core 0.17.0, the accounts feature is deprecated, and can only still be
  used with the flag `--deprecatedrpc=accounts` passed to `bitcoind`. As of 0.18 it will
  be removed entirely. Hence Joinmarket has switched over to using the labels feature, instead
  of the accounts feature, as of this 0.4.0 release, meaning you should notice no effect when
  upgrading to 0.17.0. For more details see the [PR](https://github.com/JoinMarket-Org/joinmarket-clientserver/pull/186).
  
  `b52bc06` Switch over to using labels instead of accounts
  
  ### Order chooser improvement
  
  This is a small and probably near-invisible change, once configured, but may actually be *very*
  important and so is worth understanding:
  
  One weakness of Joinmarket's model is that Takers are very price sensitive (using an exponential
  distribution of weighting by price, by default, with the order-choose method (1) `weighted_order_choose`).
  The other two non-default options were: (2) pick orders manually (great, but very fiddly/annoying) and
  (3) `cheapest-order-choose`, which obviously is maximally price sensitive.
  
  The problem with this heavy price-sensitivity is that Sybils, i.e. attackers who want to participate
  in a maximum number of joins to block them or to gain more probabilistic information, or other advantages,
  can get a lot of leverage from simply offering ultra-low fees compared to the current market. But zero
  fee sensitivity is also senseless, since the whole point is to have an actual market, i.e. prices must matter.
  
  One sensible trade-off is to have the Taker choose a maximum price they're willing to pay, but to be randomly choosing
  fees within that range. And that's what the new default order-choosing mechanism (4) `random_under_max_order_choose` is
  doing. You choose a maximum absolute number of satoshis per coinjoin counterparty, and a maximum relative fraction
  per counterparty, and orders which violate *both* of those limits are rejected. This can be set on the command line,
  as a flag, or in the `joinmarket.cfg` file. You can also override the default and go back to any of the three previously
  existing order-choose algorithms.
  
  Note that the defaults offered to you are randomized; we don't want all Takers using the same default maximum value, since
  that will lead to artificial crowding of fees near those levels; as implemented, this can't happen.
  
  `a2c74ee` add random-under-max order chooser
  
  ### Various other minor fixes
  
  Non-developers can safely ignore these changes. The last four are modifications
  to the installation scripts, in case that is relevant to your interests.
  
  55c51a9 Remove jmtainter script, not used or maintained currently
  
  03ee77b fix issues highlighted by flake8
  
  9d72573 add flake8 config and enable in travis
  
  bdbf62b fix flake8 warning
  
  59a998f fix int assertions
  
  ebcb640 fix amount fraction comment in tumblerguide
  
  316f866 use libsecp256 @d333521 for secp256k1-py
  
  be1374c install script fixed
  
  a057b87 add setupall.py --all mode
  
  51eb77e update libsodium url and core to v0.16.3 in docker
  
  
  Credits
  =======
  
  Thanks to everyone who directly contributed to this release -
  
  - @undeath
  - @fivepiece
  - @AdamISZ
  - @chris-belcher
  - @kristapsk
  - @mighty-merganser
  
  And thanks also to those who submitted bug reports, tested and otherwise helped out.
  