A new major Groestlcoin Core version 2.11.0 is now available for download bringing both new features and bug fixes, so it is recommended to upgrade to it if you are running a full Groestlcoin node or a local Groestlcoin Core wallet.

v2.11.0 is now the official release version of Groestlcoin Core. On top of the new features, this update contains very important security fixes and all users MUST upgrade to this version as soon as possible. Pool operators, P2Pool and solo miners especially, as once BIP 66 is enforced, blockversion 112 (aka 1) and blockversion 2 will be rejected from the network entirely and only blockversion 3 will be accepted.What's new in version v2.11.0?This is a major release of Groestlcoin Core, featuring the technical equivalent of Bitcoin v0.11.0 but with Groestlcoin specific patches. On a general level, most of what is new is is hidden where block synchronization and various internals are considerably faster and more efficient, and it has several major privacy improvements. The most significant changes include:• Qt dependency changed. Version upgraded to 5.5.• OpenSSL dependency changed. Version upgraded to 1.0.2a (19 March 2015).• BerkeleyDB dependency changed. Version for Windows and MAC upgraded to 5.3.21 (11 May 2012).• Protocolversion changed to 70002• Blockversion 112 interpreted as version 1. All new blocks will have blockversion 3, but v2.11.0 clients will also accept blockversion 1 (v112) and blockversion 2 blocks until 95% of all blocks will be blockversion 3. After this moment all blockversion 1 and blockversion 2 will be rejected.• All possible languages added.• New alert keys added.• Canonical name for .GroestlCoin in UNIX changed to use all lowercase: .groestlcoin.• Extra main seeds added.• New testnet created.• Comes now with a installer.• Transaction-URL support of third parties blockexplorers.• Coin control support.• Ability to open Groestlcoin URI or payment request.• Ability to spent unconfirmed coins.• Ability to see receive and send addresses.• Groestlcoin-cli. Another change in the v2.11.0 release is moving away from the groestlcoind executable functioning both as a server and as a RPC client. The RPC client functionality (“tell the running groestlcoin daemon to do THIS”) was split into a separate executable, ‘groestlcoin-cli’.• Transaction malleability-related fixes• Autotools build system. For v2.11.0 we switched to an autotools-based build system instead of individual makefiles. Using the standard “./autogen.sh; ./configure; make” to build Groestlcoin-Qt and Groestlcoind makes it easier for experienced open source developers to contribute to the project.• Rebranding to Groestlcoin Core. To reduce confusion between Groestlcoin-the-network and Groestlcoin-the-software we have renamed the reference client to Groestlcoin Core.• OP_RETURN and data in the block chain support.• Standard script rules relaxed for P2SH addresses.• Watch-only wallet support. This allows the wallet to track transactions to and form wallets for which you know the address of but do not have the private key to.• Memory usage optimization. There have been many changes in this release to reduce the default memory usage of a node.• Experimental support for big-endian CPU architectures was added in this release.• Privacy: Stream isolation for Tor. This release adds functionality to create a new circuit for every peer connection, when the software is used with Tor.• Privacy: Disable wallet transaction broadcast• Block file pruning for nodes (without wallet). This release supports running a fully validating node without maintaining a copy of the raw block and undo data on disk. Pruning is disabled by default.• Faster blockchain synchronization due to headers-first synchronization and support for downloading blocks in parallel. Downloading the blockchain is now much quicker and can be completed within a half hour instead of taking hours for some users.• A REST interface which allows unauthenticated access to public node data when the -rest flag is specified.• RPC Server “Warm-Up” Mode which starts earlier than previous versions. This helps users or services relying on it know that the server has already started and will be available soon.• Improved signing security. This is due to using the libsecp256k1 library for signing instead of OpenSSL. libsecp256k1 is a cryptographic library optimized for elliptic curve uses which Groestlcoin relies on and was created by Bitcoin Core developer Pieter Wuille. Featuring better security, via hardening against timing leaks and derandomization, this library is believed to be better tested and more thoroughly reviewed than the implementation in OpenSSL.• Improved algorithm used for fee estimation. This release automatically estimates how high a transaction fee (or how high a priority) transactions require to be confirmed quickly.• Consensus library. Starting from v2.11.0, the Groestlcoin Core distribution includes a consensus library. The purpose of this library is to make the verification functionality that is critical to Groestlcoin’s consensus available to other applications, e.g. alternative node implementations.• New utility applications including groestlcoin-tx for transaction related functionality and groestlcoin-cli for RPC command line functionality as groestlcoind no longer accepts them.• Strict DER encoding for signatures (BIP 66). This introduces block version 3 and a new consensus rule which prevents non-standard transactions from being included in blocks. This also removes the dependency on OpenSSL’s signature parsing. Eventually, libsecp256k1 will be used for all consensus related tasks, depreciating the need for OpenSSL entirely.• RPC Access Changes. RPC access now supports binary network addresses. This means that you can specify a single IP address, a CIDR network address or a netmask for accessing the RPC service. Please note, wildcard string matching no longer works and will display an error in the debug.log file when you attempt to use use a wildcard string in the rpcallowip= variable, either as a config setting or launch parameter. Note: IPv6 addresses can also be used.• Added option -alerts’ to opt out of the network alert system. Please note that disabling network alerts should only be used by power users as this system is used for network emergencies and important security releases. The default behavior is that network alerts are enabled.• Detect and reject LibreSSL. This prevents a non-approved SSL library being used for compiling Groestlcoin Core, preventing potential consensus compatibility issues.• Improved getbalance RPC functionality to allow the user to display zero confirmation transactions (this works with watch-only addresses as well).It is appreciated if feedback of the following is provided:1. Can you receive coins? (small amounts to avoid losing them)2. Can you send coins?3. Can you view your transaction on a third party blockexplorer (restart the client after entering the url of the blockexplorer) ?4. Can you use the wallet with TOR?5. Are you able to backup your wallet (wallet.dat) file?6. Are you able to encrypt your wallet (wallet.dat) file?7. Are you able to use watch-only function?8. How long does it take to fully synchronize?9. Are you able to sign/verify messages?10. Are you able to see you send/receive addresses?11. Are you able to use the wallet in your local language?The application may have unfound bugs and problems. Please report using the issue tracker at github: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/Groestlcoin-Qt (on Mac).Linux users: Canonical name for .GroestlCoin in Linux is changed to use all lowercase: .groestlcoin. Please make a link as a solution: ln .GroestlCoin .groestlcoin and rename the GroestlCoin.conf to groestlcoin.conf. And copy over groestlcoind/Groestlcoin-qt.Download the Windows Wallet (64 bit) here: https://github.com/GroestlCoin/groestlcoin/releases/download/v2.11.0/groestlcoin_x64.msi Download the Windows Wallet (32 bit) here: https://github.com/GroestlCoin/groestlcoin/releases/download/v2.11.0/groestlcoin_x86.msi Download the MAC Wallet here: https://github.com/GroestlCoin/groestlcoin/releases/download/v2.11.0/Groestlcoin-Qt.dmg Source code:Build instructions for Linux can be found here: https://github.com/GroestlCoin/groestlcoin/blob/master/doc/build-unix.md Build instructions for OSX can be found here: https://github.com/GroestlCoin/groestlcoin/blob/master/doc/build-osx.md Build instructions for Windows can be found here: https://github.com/GroestlCoin/groestlcoin/blob/master/doc/build-windows.md