Groestlcoin June ‘21 Developer Update

Groestlcoin News
9 min readJun 22, 2021


The past few months have been a pretty wild ride for Groestlcoin and Cryptocurrency in general, and today being no exception. Both Bitcoin and Groestlcoin both hit USD all-time-high values and have since fallen greatly in fiat value but continue to raise the bar on core fundamentals that other cryptocurrencies can look up to. In addition, meme coins have brought in a wave of new users to Cryptocurrency. It is now down to everyone in the existing cryptocurrency community to educate on the importance of real fundamental cryptocurrencies such as Bitcoin and Groestlcoin.

Quick Links / Contents

  • Exchanges and Advancements (Already Announced)
  • Social and Marketing (What we’ve been doing)
  • Today’s Development Updates
  • Socials / Support

Exchanges and Advancements

  • DigiFinex added a USDT Pairing for Groestlcoin.
  • PolisPay added additional eligible countries to buy gift cards with $GRS
  • Groestlcoin added to Binance Pay, a payment processor by Binance Exchange that can be used by any supported e-commerce website.
  • Groestlcoin partnered with travalacom to offer community members and Binance users the ability to purchase holidays with Groestlcoin, offering a 10% cashback offer for over a month.
  • Groestlcoin Developers collaborated with Knit.Finance to wrap Groestlcoin into smart chains such as Ethereum, BSC, Matic and Moonbeam.
  • Groestlcoin was integrated into Microsoft Azure Blockchain Template
  • Groestlcoin partnered with market-leading Simplex for an even better fiat-on-ramp experience with Simplex partners such as Changelly, Guarda and Coinomi.

Social and Marketing

  • We have launched this new Medium platform to help deliver Groestlcoin news and reach a new audience.
  • We have added a new Telegram group specifically for marketing ideas; join here!
  • We have replaced the Telegram Groestlpub with a new Groestlpub. Groestlpub is a more unregulated chat than the formal Groestlcoin chat, which we rather have discussing fundamentals. Groestlpub is for price talks and general discussions. Join here:
    Main Chat:
  • Utilising the power of Tedicross, we have combined every formal Groestlcoin Telegram chat with Discord! So you can join a single Discord group for all channels instead of joining multiple, join Discord here!
  • We have cracked down on the security of our Discord channel, requiring a captcha to participate in chat fully. Discord Insights has shown that this has cut down on scammers and spammers by around 90%.
  • We will soon launch a marketing bounty program, offering money from the marketing funds or using the marketing funds to offer memberships such as Spotify Premium and Discord Nitro — Utilising the power of Groestlcoin collaborations paying directly with Groestlcoin.
  • We wrote some how-to articles on sending GRS from the deprecated Groestlpay into Binance, here (mobile) and here (desktop).
  • We created a marketing banner for GRS Pay.

Today’s Development Updates

  • Groestltip Relaunch
  • GRS Pay Update
  • Groestlcoin HWI (Hardware Wallet Interface)
  • GRS Pay Vault Update
  • Groestlcoin Core 2.21.1 Update
  • Electrum-GRS 4.1.2 Update
  • Android Electrum-GRS 4.1.2 Update
  • Electrum Personal Server 0.2.2 Update
  • Groestlcoin Eclair 0.6.0 Lightning Implementation Update
  • Groestlcoin C-Lightning 0.10.0 Implementation Update
  • NEW — Groestlcoin RPC Auth Config Generator

Groestltip Relaunch

GroestlTip utilises the power of Streamlabs to provide a standalone web application that gives streamers the ability to accept tips in Groestlcoin, with no fees and no charge-backs. Paypal tips are also still built-in to this platform for an all-in-one experience.

Groestltip was originally developed in 2018 via a bounty but has not been supported since and has now been taken on by core developers to ensure the platform remains up and stable.

Start Using Groestltip Now


  • Streamlabs and Twitch support
  • xpub support (only addresses starting with an F currently)
  • Paypal support
  • Enhanced privacy
  • No transaction fees (other than network fees)
  • No processing fees
  • No middleman
  • No KYC
  • Built with Python
  • Open Source — MIT License

View the Source Code here!

GRS Pay — Mainnet & Testnet

GRSPay is the go-to web app for retailers to accept Groestlcoin as payment in their stores. It is a free, open-source Groestlcoin payment processor which allows you to receive payments in Groestlcoin with no fees, transaction cost or intermediary.

GRSPay is a non-custodial invoicing system that eliminates the involvement of a third party. Payments with GRSPay go directly to your wallet, which increases privacy and security. Your private keys are never required or uploaded to the server, and there is no address re-use. Instead, each invoice generates a new address derived from your xpub or zpub key.

Start Using GRSPay Now!

Start Using GRSPay on TestNet now!

What’s New?

  • GRSPay now has support for Ecommerce Apps for Shopify integration! For a full guide on how to implement Shopify into your GRSPay, please go here.
  • Support for WebAuthN/FIDO2 as a second factor.

Set up GRSPay now with these guides:

View the Source Code here!

Groestlcoin HWI 2.0.1

Groestlcoin Hardware Wallet Interface (HWI) is a Python library and command-line tool for interacting with hardware wallets.

Groestlcoin Hardware Wallet Interface (HWI) provides a standard way for software to work with hardware wallets without implementing device-specific drivers.

Caveat emptor: Inclusion of a specific hardware wallet vendor does not imply any endorsement of quality or security.

What’s New?

  • Support for Python 3.9
  • Trezor allows transactions with OP_RETURN outputs.
  • Full type annotations within hwilib and type-checking
  • Device support policy
  • Enforce that Ledger is in either the Groestlcoin or Groestlcoin Testnet apps
  • Overhauled descriptors implementation to be similar to Groestlcoin Core’s descriptors implementation
  • Overhauled HardwareWalletClient functions to return the correct objects rather than string dictionaries.
  • Raise errors and exceptions instead of returning string dictionary with errors
  • Removed option to provide redeem script to display address
  • Internalise some dependencies
  • Command changes
  • Several fixes for Ledger, Trezor One and Trezor T implementations
  • Several fixes for device enumeration
  • Fixes to binaries crashing when using keyboard shortcuts

Download Groestlcoin HWI here!

View the Source Code here!

GRS Pay Vault

GRS Pay Vault is a separate app, locally hosted on your own PC, which GRSPay Server connects to and asks for permission. Once permission is granted, GRSPay can integrate with any hardware wallet connected to your PC. In addition, the Vault gives you the ability to import your wallet and spend incoming funds with a simple confirmation on your device with your keys never leaving your hardware device.

What’s New?

  • Updated HWI to 2.0.1, offering additional support for more hardware wallets.

To download this latest release, click here.

For the Source Code, please click here.

Groestlcoin Core 2.21.1 Update

Groestlcoin V2.21.1 is now the official release version of Groestlcoin Core. It is recommended to upgrade to this version as soon as possible.

What’s new?

This is a minor release of Groestlcoin Core with Taproot Soft Fork changes, featuring the technical equivalent of Bitcoin Core v0.21.1 but with Groestlcoin-specific patches. On a general level, most of what is new are the activation method for Taproot is now being managed using a variation of BIP9 version bits called Speedy Trial (described in BIP341).

See how to upgrade from a previous version here!

Download and Install Groestlcoin Core 2.21.1 here!

View the Source Code here!

Electrum-GRS 4.1.2

Electrum-GRS is the go-to thin-client for Groestlcoin for Windows, Mac OS and Linux, based on a client-server protocol. Electrum-GRS supports multi-signature wallets and does not require you to download the entire blockchain. This update is the second major release for supporting the Groestlcoin Lightning Network.

What’s New?

  • The wallet creation wizard no longer asks for a seed type. However, legacy seed types can still be created via the command line.
  • Paid invoices (both incoming and outgoing) are automatically removed from the send/receive lists of the GUI (one confirmation is needed for on-chain invoices). Once removed from the list, invoice details can be accessed from the transaction history.
  • Lightning Network Recoverable Channels — Recovery data is added to the channel funding transaction using an OP_RETURN. This makes it possible to recover a static backup of the channel from the wallet seed.
  • Trampoline Routing — Trampoline is a solution that allows light clients to delegate path-finding on the Lightning Network so that they do not have to download the entire network graph.
  • Lightning Network now supports multi-part payments.
  • Lightning Network now supports upfront-shutdown-script
  • The “increase fee” dialogue now has advanced options and offers the choice between different RBF strategies.
  • Some deprecated features have now been removed.
  • Bug fixes and performance improvements.
  • For a full, more in-depth view into the changes to the Lightning Network, removed/replaced deprecated features and bug fixes, please click here.

Download and Install Electrum-GRS 2.1.4 here!

Download the Electrum-GRS 2.1.4 Server Installer here! (Not required to use the client)

View the Server Source Code here!

View the Client Source Code here!

Android Electrum-GRS 4.1.2

Android Electrum-GRS is the Android equivalent of Electrum-GRS, following a different release schedule and prioritising features required from a mobile wallet, which may be (and usually are) different from the Desktop equivalent.

What’s New?

  • Password unification — When the Android app is started, the entered password is checked against all wallets in the directory. If the password is correct, all wallets will be encrypted, and any new wallets will use the same password. If the password is changed, the password will be changed for all wallets.
  • Submarine swaps are now available on Kivy/Android.
  • PIN reset — If the password is unified, the PIN can be reset by providing the password.
  • On-Chain fees have been removed from the settings dialogue. Instead, the fee slider is shown to the user each time an on-chain transaction is performed.
  • Minor bug fixes

Download and Install Android Electrum-GRS 2.1.4 here!

Electrum Personal Server 0.2.2

Groestlcoin Electrum Personal Server aims to make using Electrum groestlcoin wallet more secure and more private. In addition, it makes it easy to connect your Electrum-GRS wallet to your own full node.

What’s New?

  • When starting the server and initially importing addresses, significant performance improvements, better enabling lower-powered devices such as Raspberry Pi to run the server.
  • Close the connection to the client if it requests an unknown address or if the connection to the Groestlcoin Core node is lost.
  • Increase default polling interval to ensure the server is more responsive to new transactions and confirmations.
  • Rewrite mempool handling always to be responsive.
  • Reduce spam in debug log and info log.
  • Various performance and bug fixes.

Download and Install Electrum Personal Server here!

View the Source Code here!

Groestlcoin Eclair 0.6.0 (Lightning Network Implementation)

Groestlcoin Eclair (French for Lightning) is a Scala implementation of the Lightning Network. It can be run with or without a GUI, and a JSON API is also available. Groestlcoin Eclair requires Groestlcoin Core 2.18.2 to 2.21.1. If you are upgrading an existing wallet, you need to create a new address and send all your funds to that address.

What’s New?

  • Wumbo channels
  • Static Remote Key
  • Improvements to path-finding and MPP
  • PostgreSQL beta support
  • Human-readable features
  • Ability to add plugins
  • Anchor Outputs
  • Keysend
  • Cluster Mode
  • Blockcain watchdogs
  • Seed segregation
  • Improved start-up performance
  • Gossip sync improvements

Download and Install Eclair 0.6.0 here!

Note — There are two versions, a headless command-line version (Eclair-node), and one with a GUI (JavaFX GUI).

View the Source Code here!

Groestlcoin C-Lightning 0.10.0

Groestlcoin C-Lightning is a specification-compliant Lightning Network implementation, written in C.

What’s New?

  • “pay” has been refined and improved across various less-common scenarios.
  • “listpeers” shows the current fee rate and unilateral close fee.
  • “listforwards” can now filter by channel status, and in or out channels.
  • “fundpsbt” and “utxopsbt” have a new “excess_as_change” parameter if you don’t want to add it yourself.
  • “connect” returns the address we connected to (and “direction” tells you if they connected to us instead).
  • “fundchannel_complete” takes a PSBT, removing a common cause of tragic opening failures: “txprepare” and “withdraw” now provide a PSBT for convenience too.
  • Use minimum fees in regtest mode.
  • All hooks are now registerable my multiple plugins at once.
  • Performance and stability improvements.

View how to Install on Linux here!

View how to Install on MacOS here!

View the Source Code here!

(NEW!) RPC Auth Config Generator

Groestlcoin Core RPC Auth Generator: Anyone who runs software that needs to talk to their own Groestlcoin Core node will need to configure that node to allow RPC access with the appropriate authentication. Groestlcoin Core’s rpcauth option requires the value to be in the form of: [username]:[saltedhashedpassword]

This tool makes it easier for users who are unfamiliar with running command line scripts to create the salted, hashed password value.

Live version available at But it is recommended to download Groestlcoin Core RPC Auth Generator offline and run it on your pc. Open index.html to get started.

Download Groestlcoin Core RPC Auth Generator here!

View the Source Code here!


For help and support with any Groestlcoin products, or just for a discussion or chat, please visit our social channels where the community will be more than welcome to help!



Everywhere Else…

For a full list of our social channels, please visit this medium article which lists every social channel:

Alternate News Link:

Thank you to everyone who has contributed to these developments. On to the next development update on 22nd September 2021!