Bitcoin Forum

Upgrading and downgrading
How to Upgrade

If you are running an older version, shut it down. Wait until it has completely shut down (which might take a few minutes for older versions), then run the installer (on Windows) or just copy over /Applications/Bitcoin-Qt (on Mac) or bitcoind/bitcoin-qt (on Linux).

If you are upgrading from version 0.7.2 or earlier, the first time you run 0.10.0 your blockchain files will be re-indexed, which will take anywhere from 30 minutes to several hours, depending on the speed of your machine.
Downgrading warning

Because release 0.10.0 makes use of headers-first synchronization and parallel block download (see further), the block files and databases are not backwards-compatible with older versions of Bitcoin Core:

    Blocks will be stored on disk out of order (in the order they are received, really), which makes it incompatible with some tools or other programs. Reindexing using earlier versions will also not work anymore as a result of this.

    The block index database will now hold headers for which no block is stored on disk, which earlier versions won't support.

If you want to be able to downgrade smoothly, make a backup of your entire data directory. Without this your node will need start syncing (or importing from bootstrap.dat) anew afterwards.

This does not affect wallet forward or backward compatibility.
Notable changes
Faster synchronization

Bitcoin Core now uses 'headers-first synchronization'. This means that we first ask peers for block headers (a total of 27 megabytes, as of December 2014) and validate those. In a second stage, when the headers have been discovered, we download the blocks. However, as we already know about the whole chain in advance, the blocks can be downloaded in parallel from all available peers.

In practice, this means a much faster and more robust synchronization. On recent hardware with a decent network link, it can be as little as 3 hours for an initial full synchronization. You may notice a slower progress in the very first few minutes, when headers are still being fetched and verified, but it should gain speed afterwards.

A few RPCs were added/updated as a result of this:

    getblockchaininfo now returns the number of validated headers in addition to the number of validated blocks.
    getpeerinfo lists both the number of blocks and headers we know we have in common with each peer. While synchronizing, the heights of the blocks that we have requested from peers (but haven't received yet) are also listed as 'inflight'.
    A new RPC getchaintips lists all known branches of the block chain, including those we only have headers for.

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.

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.

New command line options for fee estimation:

    -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 commands for fee estimation:

    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.

RPC access control changes

Subnet matching for the purpose of access control is now done by matching the binary network address, instead of with string wildcard matching. For the user this means that -rpcallowip takes a subnet specification, which can be

    a single IP address (e.g. 1.2.3.4 or fe80::0012:3456:789a:bcde)
    a network/CIDR (e.g. 1.2.3.0/24 or fe80::0000/64)
    a network/netmask (e.g. 1.2.3.4/255.255.255.0 or fe80::0012:3456:789a:bcde/ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff)

An arbitrary number of -rpcallow arguments can be given. An incoming connection will be accepted if its origin address matches one of them.

REST interface

A new HTTP API is exposed when running with the -rest flag, which allows unauthenticated access to public node data.

It is served on the same port as RPC, but does not need a password, and uses plain HTTP instead of JSON-RPC.

Assuming a local RPC server running on port 8332, it is possible to request:

    Blocks: http://localhost:8332/rest/block/HASH.EXT
    Blocks without transactions: http://localhost:8332/block/notxdetails/HASH.EXT
    Transactions (requires -txindex): http://localhost:8332/tx/HASH.EXT

In every case, EXT can be bin (for raw binary data), hex (for hex-encoded binary) or json.

For more details, see the doc/REST-interface.md document in the repository.
RPC Server "Warm-Up" Mode

The RPC server is started earlier now, before most of the expensive intialisations like loading the block index. It is available now almost immediately after starting the process. However, until all initialisations are done, it always returns an immediate error with code -28 to all calls.

This new behaviour can be useful for clients to know that a server is already started and will be available soon (for instance, so that they do not have to start it themselves).
Improved signing security

For 0.10 the security of signing against unusual attacks has been improved by making the signatures constant time and deterministic.

This change is a result of switching signing to use libsecp256k1 instead of OpenSSL. Libsecp256k1 is a cryptographic library optimized for the curve Bitcoin uses which was created by Bitcoin Core developer Pieter Wuille.

There exist attacks[1] against most ECC implementations where an attacker on shared virtual machine hardware could extract a private key if they could cause a target to sign using the same key hundreds of times. While using shared hosts and reusing keys are inadvisable for other reasons, it's a better practice to avoid the exposure.

OpenSSL has code in their source repository for derandomization and reduction in timing leaks, and we've eagerly wanted to use it for a long time but this functionality has still not made its way into a released version of OpenSSL. Libsecp256k1 achieves significantly stronger protection: As far as we're aware this is the only deployed implementation of constant time signing for the curve Bitcoin uses and we have reason to believe that libsecp256k1 is better tested and more thoroughly reviewed than the implementation in OpenSSL.

[1] https://eprint.iacr.org/2014/161.pdf
Watch-only addresses in the wallet

The wallet can now track transactions to addresses (or scripts) for which you do not have the private keys.

This can be used to track payments without needing the private keys online on a possibly vulnerable system. In addition, it can help for (manual) construction of multisig transactions where you are only one of the signers.

One new RPC, importaddress, is added which functions similarly to importprivkey, but instead takes an address or script (in hexadecimal) as argument. After using it, outputs credited to this address or script are considered to be yours.

The following RPCs have optional support for watch-only addresses: getbalance, listreceivedbyaddress, listreceivedbyaccount, listtransactions, listaccounts, listsinceblock, gettransaction. See the RPC documentation for those methods for more information.

Compared to using getrawtransaction, this mechanism does not require -txindex, scales better, integrates better with the wallet, and is compatible with future block chain pruning functionality. It does mean the address needs to added to the wallet before the payment, though.
Consensus library

Starting from 0.10.0, the Bitcoin Core distribution includes a consensus library.

The purpose of this library is to make the verification functionality that is critical to Bitcoin's consensus available to other applications, e.g. to language bindings such as python_bitcoinlib or alternative node implementations.

This library is called libbitcoinconsensus.so (or, .dll for Windows). Its interface is defined in the C header bitcoinconsensus.h.

In its initial version the API includes two functions:

    bitcoinconsensus_verify_script verifies a script. It returns whether the indicated input of the provided serialized transaction correctly spends the passed scriptPubKey under additional constraints indicated by flags
    bitcoinconsensus_version returns the API version, currently at an experimental 0

The functionality is planned to be extended to e.g. UTXO management in upcoming releases, but the interface for existing methods should remain stable.
Standard script rules relaxed for P2SH addresses

The IsStandard() rules have been almost completely removed for P2SH redemption scripts, allowing applications to make use of any valid script type, such as "n-of-m OR y", hash-locked oracle addresses, etc. While the Bitcoin protocol has always supported these types of script, actually using them on mainnet has been previously inconvenient as standard Bitcoin Core nodes wouldn't relay them to miners, nor would most miners include them in blocks they mined.
bitcoin-tx

It has been observed that many of the RPC functions offered by bitcoind are "pure functions", and operate independently of the bitcoind wallet. This included many of the RPC "raw transaction" API functions, such as createrawtransaction.

bitcoin-tx is a newly introduced command line utility designed to enable easy manipulation of bitcoin transactions. A summary of its operation may be obtained via "bitcoin-tx --help" Transactions may be created or signed in a manner similar to the RPC raw tx API. Transactions may be updated, deleting inputs or outputs, or appending new inputs and outputs. Custom scripts may be easily composed using a simple text notation, borrowed from the bitcoin test suite.

This tool may be used for experimenting with new transaction types, signing multi-party transactions, and many other uses. Long term, the goal is to deprecate and remove "pure function" RPC API calls, as those do not require a server round-trip to execute.

Other utilities "bitcoin-key" and "bitcoin-script" have been proposed, making key and script operations easily accessible via command line.

Credits

Thanks to everyone who contributed to this release:

    21E14
    Adam Weiss
    Aitor Pazos
    Alexander Jeng
    Alex Morcos
    Alon Muroch
    Andreas Schildbach
    Andrew Poelstra
    Andy Alness
    Ashley Holman
    Benedict Chan
    Ben Holden-Crowther
    Bryan Bishop
    BtcDrak
    Christian von Roques
    Clinton Christian
    Cory Fields
    Cozz Lovan
    daniel
    Daniel Kraft
    David Hill
    Derek701
    dexX7
    dllud
    Dominyk Tiller
    Doug
    elichai
    elkingtowa
    ENikS
    Eric Shaw
    Federico Bond
    Francis GASCHET
    Gavin Andresen
    Giuseppe Mazzotta
    Glenn Willen
    Gregory Maxwell
    gubatron
    HarryWu
    himynameismartin
    Huang Le
    Ian Carroll
    imharrywu
    Jameson Lopp
    Janusz Lenar
    JaSK
    Jeff Garzik
    JL2035
    Johnathan Corgan
    Jonas Schnelli
    jtimon
    Julian Haight
    Kamil Domanski
    kazcw
    kevin
    kiwigb
    Kosta Zertsekel
    LongShao007
    Luke Dashjr
    Mark Friedenbach
    Mathy Vanvoorden
    Matt Corallo
    Matthew Bogosian
    Micha
    Michael Ford
    Mike Hearn
    mrbandrews
    mruddy
    ntrgn
    Otto Allmendinger
    paveljanik
    Pavel Vasin
    Peter Todd
    phantomcircuit
    Philip Kaufmann
    Pieter Wuille
    pryds
    randy-waterhouse
    R E Broadley
    Rose Toomey
    Ross Nicoll
    Roy Badami
    Ruben Dario Ponticelli
    Rune K. Svendsen
    Ryan X. Charles
    Saivann
    sandakersmann
    SergioDemianLerner
    shshshsh
    sinetek
    Stuart Cardall
    Suhas Daftuar
    Tawanda Kembo
    Teran McKinney
    tm314159
    Tom Harding
    Trevin Hofmann
    Whit J
    Wladimir J. van der Laan
    Yoichi Hirai
    Zak Wilcox

As well as everyone that helped translating on Transifex.

It's full of great new features. You'll enjoy it :)

Loving the fact you can now have watch-only addresses, making stuff a lot more secure.

do we nneed to install it or it will update by its self?

do we nneed to install it or it will update by its self?

It's full of great new features. You'll enjoy it :)

Loving the fact you can now have watch-only addresses, making stuff a lot more secure.

watch-only addresses

http://www.reddit.com/r/Bitcoin/comments/2a222h/support_for_watchonly_addresses_merged_into/

Wallet can be used w/out private keys (key monitoring). This enables certain multi-node monitoring designs as well.

If you have a cold storage wallet and you are paranoid about your balance, you can just import the public (not private) keys into your watch-only wallet. You can then easily check your balance on that wallet without running the risk of having your private keys on an Internet-connected machine.

It's full of great new features. You'll enjoy it :)

Loving the fact you can now have watch-only addresses, making stuff a lot more secure.

You can then easily check your balance on that wallet without running the risk of having your private keys on an Internet-connected machine.

Note that the final 0.10.0 isn't available yet.
Current status is Release Candidate 1.

Why isn't this listed on the forum news link above? It still shows 0.9.3.

Why isn't this listed on the forum news link above? It still shows 0.9.3.

It's still a release candidate.

I see, thanks.

Why isn't this listed on the forum news link above? It still shows 0.9.3.

They just changed it to "Help test the latest unstable version of Bitcoin Core: 0.10.0rc1." Lol and i like your signature.  :D

It's still a release candidate.

Great work indeed, we're moving forward nicely.
I wonder what 1.0.0 would bring us then.  :o

They just changed it to "Help test the latest unstable version of Bitcoin Core: 0.10.0rc1." Lol and i like your signature.  :D

RC1 uses BerkeleyDB?

It's still used for the wallet. It's not used for anything else.

Our three letter friends have put pressure on the foundation to introduce another buggy Bitcoin Core, I am willing to bet that within a couple of months catastrophic bugs will be found once again (whoops).

What exactly are you talking about? Mine still works fine and hasn't crashed.

Our three letter friends have put pressure on the foundation to introduce another buggy Bitcoin Core, I am willing to bet that within a couple of months catastrophic bugs will be found once again (whoops).

Our three letter friends have put pressure on the foundation to introduce another buggy Bitcoin Core, I am willing to bet that within a couple of months catastrophic bugs will be found once again (whoops).

That's why it's labelled "unstable". ::) Normal users shouldn't be using it. They should stick with the "stable" releases. The purpose of this release is to find catastrophic bugs. No three letter agencies required.

finally come 0.1.x.x with lots of new features that's awesome.But I would wait until the final version release.

when the "delete address" will be added?, it's not that important i know, but it's always a plus to have

when the "delete address" will be added? it's not that important i know, but it's always a plus to have

Can someone tell me how the version numbering works?

I was sure after all the 0.9.x versions the next was logically.....1.xxxx

0.1 + 0.9 = 0.10

Really guys??

There is a reason it has 0.10.0. After 9 comes 10, or did you not go to primary school?

Thanks for the condescending response. I'm sure women find this attractive.

Thanks for the condescending response. I'm sure women find this attractive.

Good work guys. keep it up. This is great improvement. But still I am waiting for final version. :)

But still I am waiting for final version. :)

You mean the stable version of 0.10.0 I'm assuming?

You mean the stable version of 0.10.0 I'm assuming?

With most of the software version numbering systems I've been involved in:

• Incrementing the first number represents a major change in the architecture and underlying design of the software.
• Incremening the second number represents new enhancements, and significant bug fixes
• Incrementing the third number represents minor bug fixes and very small changes to features (often considered a "maintenance release")

So, we could easily end up on version 0.957.3 (3rd maintenance release of the 957th enhancement release of the original code base) some day if there is no compelling reason to change the first digit of the version number.

Interestingly, we often see altcoins trying to represent themselves as "Bitcoin 2.0" which is rather entertaining since there hasn't even been a "Bitcoin 1.0" yet.

Thanks Danny. It is unjust that you are not labelled as a "Legend" on here.

good work and the increased syncing is great!

So, we could easily end up on version 0.957.3 (3rd maintenance release of the 957th enhancement release of the original code base) some day if there is no compelling reason to change the first digit of the version number.

If it needs to reindex you'll have to wait for it. But it should go faster with the RC build...

You mean the option of deleting an address from a wallet?
Interesting, request, it would definitely be very useful.

yeah, right now you need to re-create a new wallet to do this, it could be doing easily with a send to other folder that hide them

anyway this version is not signed yet, it is because of the rc1 state?

It is. Grab the SHA256SUMS.asc file from the directory.

I thought Windows XP was obsolete. Is it still safe to connect one of those machines to the internet anything made by Microsoft to the Internet?

I thought Windows XP was obsolete. Is it still safe to connect one of those machines to the internet?

What makes you think that newer versions of Windows are safer?

Bit of a strawman reply here. I never mentioned anything about newer versions of Windows being safer.