Nimbus `v23.5.1` is a `medium-urgency` point release improving the compatibility of Nimbus with 3rd party validator clients and beacon nodes and introducing the support for incremental pruning. If you are still not using the `--history:prune` option, we recommend testing it in a non-production environment, as it will be enabled by default in our next release.
* The Nimbus validator client no longer accepts under-specified beacon node URLs that doesn't include a port number or a protocol scheme. When a protocol scheme is specified, Nimbus now uses the default port for the selected protocol (80 for HTTP and 443 for HTTPS):
* Nimbus now uses the withdrawal address of the validator as a default choice for the fee recipient address if the user has not provided any value in the configuration:
* The Capella-related properties `MAX_BLS_TO_EXECUTION_CHANGES`, `MAX_WITHDRAWALS_PER_PAYLOAD`, `MAX_VALIDATORS_PER_WITHDRAWALS_SWEEP` and `DOMAIN_BLS_TO_EXECUTION_CHANGE` were missing from the `/eth/v1/config/spec` REST API end-point:
* After being only briefly disconnected from the execution layer client, the Nimbus beacon node was prematurely setting the `execution_optimistic` flag when returning validator duties:
* Nimbus now allows the builder to respond 500ms later than the spec-mandated timeout in order to account for possible additional delays introduced by proxies such as mev-boost:
Nimbus `v23.5.0` is a `medium-urgency` upgrade that addresses a critical issue which was introduced in the previous version (`v23.4.0`). The issue was causing missed block proposals for users who were utilizing an external builder.
### Improvements
* After Nimbus completes a trusted node sync executed with the `--trusted-block-root` flag, it will enable signature verification of all backfilled blocks, thereby reducing the assumed trust in the specified beacon node URL to merely expected data availability rather than expected data authenticity:
* The `secp256k1` library has been upgraded to version `0.3.1`.
* Nimbus now supports an experimental extension of the Web3Signer protocol, allowing the signer server to verify certain properties of the signed block, such as the specified fee recipient:
* Nimbus was skipping block proposals due to an inappropriate triggering of the slashing protection logic when an external builder was providing a block with insufficient value to be selected under the new `--local-block-value-boost` mechanism:
* The Nimbus validator client was failing to perform sync committee duties when attached to multiple beacon nodes and when some of them were only optimistically synced:
* Nimbus was experiencing sporadic request time outs when being connected to the execution client over HTTP. Under specific circumstances this was introducing risk for missed attestation:
Nimbus `v23.4.0` is a `medium-urgency` upgrade addressing a number of low probability risks for missed block proposals, bringing performance improvements in setups relying on the Nimbus validator client, and introducing some exciting new capabilities of the Nimbus light client and Builder API implementations.
### Improvements
* Nimbus now obtains blocks from the configured builder and execution layer nodes without providing timing advantage to any source. You can use the newly added `--local-block-value-boost` option to give preference to the best block provided by an execution layer node, as long as its value is within the specified percentage of the value advertised by the best external builder. Setting this flag to a non-zero value is recommended because the usage of an external builder introduces an additional risk that the advertised block won't be published by the builder:
* The `trustedNodeSync` command features a new `--trusted-block-root` option that leverages the Nimbus light client in order to minimize the required trust in the specified Beacon API endpoint. After downloading the state snapshot, the light client will verify that it conforms to the established consensus in the network. Note that the provided `--trusted-block-root` should be somewhat recent, and that additional security precautions such as comparing the state root against block explorers are still recommended.
* Nimbus now supports the [`/eth/v1/beacon/states/{state_id}/randao`](https://ethereum.github.io/beacon-APIs/?urls.primaryName=dev#/Beacon/getStateRandao) REST API endpoint:
* Nimbus has addressed a low probability risk of missed block proposals when a late block triggers a chain re-org while an `engine_forkchoiceUpdated` request to the execution layer is in flight:
* Nimbus will no longer experience occasional response timeouts when performing a large number of concurrent HTTP requests (e.g. when configured to operate with a large number of remote keystores):
* Failed or timed out request to `engine_exchangeTransitionConfigurationV1` will no longer degrade the status of the connection to the execution layer:
Nimbus `v23.3.2` is a `low-urgency`, but mandatory upgrade providing full-support for the upcoming Capella hard-fork on Mainnet. Please upgrade at your earliest convenience - **before the 12th of April**.
* The `deposits exit` can now be executed with a path to a keystore file that was generated by `deposit-staking-cli` or `ethdo`. All users are advised to use this method for exiting, due to a [known issue](https://github.com/status-im/nimbus-eth2/issues/4216) preventing the other formerly supported methods from working:
* The metrics `beacon_light_client_finality_update_received`, `beacon_light_client_finality_update_dropped`, `beacon_light_client_optimistic_update_received` and `beacon_light_client_optimistic_update_dropped` provide information regarding the observed light client gossip traffic:
* Nimbus now recognizes the `/eth/v1/validator/beacon_committee_selections` and `/eth/v1/validator/sync_committee_selections` Beacon API end-points in accordance to the latest spec:
* Nimbus will no longer report warnings such as "Connection to EL node degraded" when paired with an execution node that hasn't been synced up to the deployment block of the validator deposit contract:
Nimbus `v23.3.1` is a `medium-urgency` point release addressing a number of accidental configuration handling breaking changes that were shipped in the `v23.3.0` release. It also improves the stability of Nimbus when paired with a Besu execution client and improves the fault-tolerance when driving multiple execution clients.
### Fixes
* Nimbus was performing `eth_getLogs` request with parameters that were exceeding the default `--rpc-max-logs-range=1000` limit on Besu. This was a non-fatal issue that resulted in slower deposit syncing speed and the frequent warning message "Connection to EL node degraded". The limit will be increased in the next mainnet release of Besu, but Nimbus `v23.3.1` honours the existing limit at the cost of a slightly slower syncing speed with all other execution clients:
*`v23.3.0` did not support Engine API URLs which don't specify a protocol in the URL (e.g. `http`, `https`, `ws` or `wss`). `v23.3.1` is backwards-compatible with all previous Nimbus releases:
*`v23.3.0` produced a parsing error on TOML configuration files that specify the `web3-url` parameter as an array of strings. `v23.3.1` is backwards-compatible with all previous Nimbus releases and introduces a new more convenient way for specifying the Engine API configuration in TOML:
*`v23.3.0` removed the hidden configuration option `--web3-force-polling` which remained in use by some users. `v23.3.1` restores the option as a deprecated one. Please note that all hidden configuration options are intended for use only by the Nimbus development team for testing purposes:
* The release addresses a potential issue where a single non-synced execution client may cause the Nimbus sync state to revert to `synced/opt`, even when all validator duties can be performed through the remaining execution clients that are still synced:
Nimbus `v23.3.0` is a `low-urgency` upgrade bringing full support for the upcoming Capella hard-fork on the Goerli testnet. Keep an eye out for future mainnet releases!
* You can increase the resilience of your setup and eliminate any downtime during upgrade procedures of the execution client by allowing your beacon node to manage multiple execution clients. To enable this mode, just specify multiple URLs through the `--el` option (alias of `--web3-url`) when starting your beacon node:
As long as any of execution clients remains operational and fully synced, Nimbus will keep performing all validator duties. To carry out an upgrade procedure without any downtime, just restart the execution clients one by one, waiting for each instance to re-sync before moving to the next one.
If you use this mode with different execution client implementations, Nimbus will act as an execution layer consensus violation detector, preventing the publishing of blocks that may trigger a catastrophic partitioning in the network.
* The metrics `engine_api_responses`, `engine_api_request_duration_seconds` and `engine_api_timeouts` provide statistics about latency and response status codes for all requests sent to each individual execution layer URL:
* Nimbus will now attempt to connect to a locally running execution client even when the options `--el` and `--jwt-secret` are not specified. This is made possible by the following proposed standard:
* Improved diagnostic messages and more spec-compliant behavior of the Nimbus validator client when being paired with a non-synced or optimistically synced beacon nodes:
* Nimbus now downloads a longer range of recent execution blocks in order to avoid potential situations where our `Eth1Data` votes fail to agree with the honest majority in the network:
Nimbus `v23.1.0` is a `low-urgency` upgrade, introducing support for on-the-fly database pruning making the storage requirements of Nimbus much more predictable on long-term time scales. When pruning is enabled, a typical beacon node expected to consume around 60 to 70 GB of storage. To take advantage of the new functionality without facing any downtime, users are advised to sync a fresh node through trusted node sync which now features a quicker history backfilling implementation.
### Improvements
* After a trusted node sync, Nimbus requires less time to complete the block
backfilling process by downloading the minimum number of historical blocks
Nimbus `v22.12.0` is a `medium-urgency` release which improves the doppelganger detection in the Nimbus validator through the use of standardized APIs that are compatible with all third-party beacon nodes. Furthermore, it addresses several inconsistencies in the behavior between the stand-alone beacon node and the validator client. This release also allows users of trusted node sync to skip downloading the entire history of validator deposits by syncing against a server that supports the standardized `/eth/v1/beacon/deposit_snapshot` REST endpoint.
### Improvements
* 60% more efficient block replaying speed brings faster REST responses and
more resilience on the network in the face of heavy forking activity and
Nimbus `v22.10.1` is a `low-urgency` point release introducing support for the official light client REST API and improving the stability of Nimbus when paired with an external block builder.
Nimbus `v22.10.0` is a `medium-urgency` release, continuing our briefly accelerated release schedule and bringing further stability and performance improvements after the merge.
* The new metrics `beacon_block_builder_proposed`, `beacon_block_builder_missed_with_fallback` and `beacon_block_builder_missed_without_fallback` can help you track the successful and failed attempts to use the configured external block builder:
* The pre-altair REST API paths `/eth2/beacon_chain/req/beacon_blocks_by_{range,root}/1/` are now deprecated and will be removed in the next Nimbus version. Since these APIs support only phase0 responses, it is unlikely that there are any remaining clients using them.
Nimbus `v22.9.1` is a `medium-urgency` upgrade addressing several frequently reported issues after the merge and bringing minor performance improvements in the post-merge world.
### Breaking changes
* Nimbus no longer supports the non-standard `/api/` prefix for the Beacon REST API. All users should migrate to the standardized `/eth/` prefix:
* Implemented the `/eth/v1/validator/register_validator`, enabling the use of an external block builder when the Nimbus beacon node is used with a validator client:
* The initial transition configuration exchange is performed after a short delay to give more time for the EL client to initialize when all services are started at the same time:
Nimbus `v22.9.0` is a `high-urgency` upgrade that fixes a critical pre-TTD block production issue affecting users that restarted their node after Bellatrix. It also improves compatibility with Besu, Prysm and slow block builders and provides a speed boost in block processing important for those running on Raspberry Pi and similar hardware.
With the merge drawing near, the focus of this release has been to include low risk changes that improve stability and compatibility - if you are unsure whether to upgrade, do reach out to us in discord to discuss your particular deployment.
A shout out to our great community for reporting and helping diagnose the issues that led up to this release - in particular Michael Sproul (Lighthouse) and Joe Clapis (Rocket Pool).
### Improvements
* Allow more time for block builder to deliver block
Nimbus `v22.8.2` is a `low-urgency` hotfix release, eliminating a risk for potential crash during block production that was introduced in the `v22.8.1` release. You can safely skip this release if you haven't enabled DEBUG logging on your beacon node, as the risk exists only when DEBUG logging is enabled.
Nimbus `v22.8.1` is a `high-urgency` upgrade, improving the stability and performance of Nimbus in post-merge networks. Upgrading is highly recommended due to improved timing of the interactions with the execution engine which may lead to higher profitability from block production, especially for users running Nethermind.
### Improvements
* More timely block proposals in the presence of a non-responsive builder node:
Nimbus `v22.8.0` is a `medium` urgency release, featuring full support for the upcoming mainnet merge! All users should upgrade at their earliest convenient, but no later than 5th of September.
> Since the network will go through the Bellatrix hard-fork on Sept 6, 2022, 11:34:47am UTC, failure to upgrade in time will result in inactivity penalties.
Please note that once the network reaches the terminal total difficulty (currently estimated to happen between 13th and 15th of September), it will no longer be possible to operate a beacon node without pairing it with a single non-shared merge-ready execution client. Nimbus is fully compatible will all execution clients and the required configuration steps for all of them are the same. Please refer to our merge guide for more details:
https://nimbus.guide/merge.html
To raise awareness of the required configuration changes, once the Bellatrix fork is activated on 6th of September, Nimbus will refuse to start unless a properly configured and authenticated Engine API end-point is provided through the command-line options `--web3-url` and `--jwt-secret`. If you need more time to complete the transition, you can temporarily run the beacon node with the command-line option `--require-engine-api-in-bellatrix=no`, but please note that such a setup will stop working once the network TTD is reached!
We would like to say a huge THANK YOU to all of our users who provided immensely valuable feedback in the many months of hard work leading to the merge and to all the fellow research and implementation teams who made this historic release possible!
Onwards and happy merging!
### Breaking changes
* Nimbus will refuse to start unless connected to a properly configured execution client in Bellatrix-enabled networks:
* The custom error code returned by Nimbus when a validator doppelganger is detected has been changed from 1031 to 129 to improve compatibility with `systemd`:
* Beta release for the Nimbus stand-alone light client, which can be used to drive any execution client without requiring a full-blown beacon node:
https://nimbus.guide/light-client-data.html
* The first spec-compliant implementation of the LibP2P protocols for serving light client data:
https://nimbus.guide/light-client-data.html
* Keystore locking prevents accidentally loading the same validator keys in multiple instances of the Nimbus beacon node and the Nimbus validator client, thus eliminating a potential slashing risk:
* Debian and RPM packages for the Nimbus beacon node and the Nimbus validator client are now available as part of the release. In the near future, Status will also provide a package repository, offering a more convenient installation:
* The Nimbus validator client now supports validator activity metrics such as `beacon_attestations_sent`, `beacon_aggregates_sent`, `beacon_attestation_sent_delay`, `beacon_blocks_sent`, `beacon_blocks_sent_delay`, `beacon_sync_committee_messages_sent`, `beacon_sync_committee_message_sent_delay`, `beacon_sync_committee_contributions_sent`:
* The sync status displayed in the Nimbus status bar and certain log messages now describes the state of the client more accurately (optimistically synced vs fully synced):
Nimbus `v22.7.0` is a `low` urgency release packing everything necessary for the [upcoming Prater/Goerli merge](https://wenmerge.com/) and introducing the [Nimbus validator client](https://nimbus.guide/validator-client.html) (currently in BETA).
### Other Improvements
* Support for fee recipient management through the [Keymanager API](https://ethereum.github.io/keymanager-APIs/#/Fee%20Recipient) and
through the [`/eth/v1/validator/prepare_beacon_proposer`](https://ethereum.github.io/beacon-APIs/#/Validator/prepareBeaconProposer) Beacon API end-point:
Nimbus `v22.6.1` is a `low-urgency` release which comes pre-configured with the correct TTD value for the Sepolia network and improves the behavior of Nimbus in merge testnets.
Nimbus `v22.6.0` brings support for the merge testnets Ropsten and Sepolia (please stay tuned for TTD announcements for the latter) and a lot of polish where we've taken the time to address a long list of UX improvements and bug fixes suggested or reported by our users. We are deeply grateful to everybody who contributed valuable feedback for this release.
* The custom error code `129` will signal a detected doppelganger on the network. This can be handled in the Nimbus's service supervisor to prevent an automatic restart:
* Incorrect encoding of the `current_epoch_participation` and `previous_epoch_participation` fields in the REST requests returning `BeaconState` results:
* The Nimbus-specific JSON-RPC service which was deprecated in version v22.3.0 is now removed. If you are currently relying on the JSON-RPC API, please consider switching to the official [REST API](https://nimbus.guide/rest-api.html). Using any of the `--rpc` flags will now result in a warning:
Nimbus `v22.5.0` is a `low-urgency` maintenance release. It implements the proposer boosting fork-choice policy and is compliant with the latest [Bellatrix specifications](https://github.com/ethereum/consensus-specs#bellatrix-also-known-as-the-merge). It also provides an early preview of our built-in support for [BLS threshold signatures](https://notes.ethereum.org/@djrtwo/blst-rfp) (via regular Web3Signer instances): this marks the first step of our long-term [secret-shared validators roadmap](https://github.com/status-im/nimbus-eth2/issues/3416) which enables node operators / staking pools to deploy Nimbus in secure high availability setups (guaranteeing ~100% uptime).
* An initial preview release fеaturing built-in support for distributed keystores, (part of our [secret shared validators roadmap]( https://github.com/status-im/nimbus-eth2/issues/3416)):
Nimbus `v22.4.0` is a `low-urgency` upgrade which brings with it further optimisations, and better user experience around [trusted node sync](https://nimbus.guide/trusted-node-sync.html). It lays the foundations for upcoming the merge hard-fork which will be fully supported in our next release (`v22.5.0`).
* The REST API now *only* returns current and relevant information in response to VC queries: in other words, information from the recent non-finalized portion of the chain history:
* Better and more consistent gossip mesh health: the `--max-peers` option now works as a target that can be exceeded by the client temporarily in order to maintain good gossip mesh health; the newly introduced `--hard-max-peers` option now acts as the hard limit that should not be exceeded (default set to `max-peers * 1.5`):
* An [ERA files](https://our.status.im/nimbus-update-march/#era-files-a-proposed-solution-to-historical-data-queries) developer preview: ERA files are an ultra-efficient long-term storage format for finalized chain history:
Nimbus `v22.3.0` is a `low-urgency` upgrade that marks the beginning of a more predictable release cadence for Nimbus. Going forward, we'll be publishing a new release each month, following a feature freeze period with intensified testing and monitoring of the introduced code changes on our dispersed fleet of mainnet validators.
> Please note that the new versioning scheme is tied to the calendar. The number 22 indicates the year of the release (2022), while 3 is the month (March). The last digit is the patch number of the release and it will have a non-zero value only when we ship a hotfix during the month.
* Extremely slow [slashing DB import](https://nimbus.guide/migration.html#step-4---import-your-slashing-protection-history) for validators with long validation history: the import should be nearly instant now
- The [JSON-RPC](https://nimbus.guide/api.html) service (`--rpc` flag) option is now deprecated. It's scheduled for removal in version `v22.6` (i.e. June of this year). If you are currently relying on the JSON-RPC API, please consider switching to the official [REST API](https://nimbus.guide/rest-api.html).
Nimbus `v1.7.0` is a `low-urgency` feature-packed upgrade, which brings support for [trusted node sync](https://nimbus.guide/trusted-node-sync.html) (also known as checkpoint sync) and HTTPS web3 providers.
Of particular note: the [Keymanager API](https://nimbus.guide/keymanager-api.html) now supports remote keystores (a.k.a web3signer keystores).
- Nimbus will no longer rewrite HTTP(S) web3 URLs to their respective WebSocket alternatives. Please review your setup to ensure you are using the desired web3 end-point.
- The peer scoring has been further tuned. As such the `--max-peers` should not be set below 70. Note that Lowering `max-peers` does not significantly improve bandwidth usage, but does increase the risk of missed attestations.
* Nimbus now treats the first `--web3-url` as a primary and preferred web3 provider. Any extra URLs are treated as fallback providers (to be used only when the primary is offline). As soon as the primary is usable again, Nimbus will switch back to it.
* The Keymanager API now supports management of remote keystores (also known as web3signer keystores):
* 128MB of savings come from exploiting a provision in the official spec, which allows clients to respond with only non-finalized blocks to network queries which request blocks by their root hash.
* A new `--rest-url` parameter for the `deposits exit` command: https://github.com/status-im/nimbus-eth2/pull/3344, https://github.com/status-im/nimbus-eth2/pull/3318
* You can now issue exits uing any beacon node which provides the [official REST API](https://nimbus.guide/rest-api.html). The Nimbus-specific [JSON-RPC API](https://nimbus.guide/api.html) will be deprecated in our next release, with a view to completely phasing it out over the next few months.
* Unnecessary CPU and bandwidth usage: https://github.com/status-im/nimbus-eth2/pull/3308
* The result of staying subsribed to sync committee topics even when there were no validators in the committee.
* Excessive logging on beacon nodes with large numbers of validators (in particular, those with `--validator-monitor-totals` enabled): https://github.com/status-im/nimbus-eth2/pull/3332
* Deviations from the spec in the REST API; this led to sub-optimal performance when Nimbus was paired with Vouch.
* Naming inconsistencies in the "totals" metrics (this was produced by the [validator monitor](https://nimbus.guide/validator-monitor.html)).
* Non-compliant implementation of the `/eth/v1/node/health` API (we were not producing HTTP status codes as mandated by the spec).
* Unnecessary restarts of the Eth1 syncing progress when the web3 provider connection was lost during sync: https://github.com/status-im/nimbus-eth2/pull/3354
* Tuned peer management: reduces the likelihood of missed attestations
* If you've seen frequent "No peers for topic" in your logs, this release will help
* Improved buffer management in the networking layer: reduces both CPU and memory usage.
* Further optimised batch verification of gossip messages: provides a 2-fold improvement in throughput.
* Comprehensive set of metrics for live validator performance monitoring in Grafana and support for producing detailed historic reward analysis in `ncli_db` (note that `ncli_db` is available only when compiling from source at the moment).
* Support for the new Keymanager API: add, remove, and migrate validators on the fly (BETA).
* Blazingly fast historical traversals in the REST API for beacon chain data mining: state caching brings up to a 10x speed-up in some common usage patterns (e.g. obtaining historic data slot by slot or epoch by epoch).
* 3x speed-up in snappy compression and decompression.
* Support for obtaining JSON payloads from the REST API.
Nimbus `v1.5.5` is a `medium-urgency` bugfix release which contains a number of significant optimisations; of particular note is a **6x speed-up in epoch processing** and **2x speed up in Altair block processing**.
In addition, `v1.5.5` adds support for the `web3signer` protocol (currently in BETA).
### We've fixed:
* The potential for missed block proposals when a third-party validator client (with at least one imported validator) is used with a Nimbus beacon node (with no imported validators)
* The web3 connection not being enabled when running third-party validator clients
* A rare condition in which the REST service becomes unavailable.
* Inappropriate error messages produced by the REST API: when a validator client is publishing the same attestations or sync committee messages through multiple beacon nodes.
### Improvements:
* 6x speed-up in epoch processing: https://github.com/status-im/nimbus-eth2/pull/3089
* 2x speed up in Altair block processing: https://github.com/status-im/nimbus-eth2/pull/3115
* A 12% (minimum) reduction in the outgoing GossipSub traffic: https://github.com/status-im/nimbus-eth2/pull/3112
* Across the board performance improvements in the REST API: https://github.com/status-im/nimbus-eth2/pull/3092
* The REST API can now report sync committee information for the next sync period: https://github.com/status-im/nimbus-eth2/pull/3133
* Added support for the web3signer protocol (beta release):
Nimbus `v1.5.4` is a `medium-urgency` hotfix release. It addresses an important issue which, in rare cases, can lead to the loss of attestations and sync committee messages. This can, in turn, lead to a reduction in rewards.
* A rare issue during the construction of sync committee contributions: invalid BLS aggregate signatures were being produced under certain conditions; this had the potential to negatively affect the peer score of the node, and impact its ability to deliver gossip messages.
* A non-spec-compliant implementation of the `/eth/v1/validator/duties/sync/{epoch}` REST API.
* A crash in the `/eth/v2/debug/beacon/states` REST API call on systems with limited stack space.
### Improvements:
* A nice little performance improvement for block verification and replay.
* Improved error messages in the REST API.
* The `/eth/v1/config/spec` REST API now returns more information regarding spec config parameters.
## Other notable changes:
* The `--log-file` option is now deprecated and may be removed in a future release (if you wish to log to a file, we recommend redirecting the standard output).
Please note that the --log-file option was previously supported only when Nimbus was built from source. If your existing configuration used the --log-file option with a binary release, upgrading to v1.5.4 will enable the log file creation (though a deprecation warning will be printed on start-up).
Nimbus `v1.5.1` is a `high-urgency` release for all users who have already upgraded to `v1.5.0`. It fixes a deposit contract syncing issue manifesting as the warning message "Eth1 chain not synced". Under specific circumstances, such a failure to sync the Eth1 chain may result in missed Eth2 block proposals, so affected users are advised to upgrade as soon as possible.
For anyone still running Nimbus v1.4.x or earlier, migrating to v1.5.1 continues to be a `medium-urgency` but *mandatory* upgrade that must be installed **before October 27th**.
Nimbus `v1.5.0` is a `medium-urgency` but *mandatory* upgrade which adds support for the upcoming beacon chain Altair hard-fork.
Please upgrade at your earliest convenience - **before the 27th of October**.
> **N.B** You must upgrade before October 27th in order to follow the mainnet beacon chain. Failure to do so will result in downtime penalties.
This is the first hard fork for the beacon chain, and while a significant amount of testing has been conducted in the run up to this release, we recommend users regularly monitor our announcement channels ([discord]() and/or the [newsletter]()) for potential updates.
To celebrate the feature complete release candidate of our REST API, we've opened up the ports on some of our fleet nodes - don't do this at home ;)
In order to interact with these, you should point your apps and tools to:
* http://unstable.mainnet.beacon-api.nimbus.team/ - `mainnet` data, the latest `unstable` [branch](https://github.com/status-im/nimbus-eth2/tree/unstable)
* http://unstable.prater.beacon-api.nimbus.team/ - `prater` testnet data, the [latest](http://unstable.mainnet.beacon-api.nimbus.team/eth/v1/node/version) `unstable` [branch](https://github.com/status-im/nimbus-eth2/tree/unstable)
Note that right now these are very much unstable testing instances. They may be unresponsive at times - so **please do not rely on them for validation**. We may also disable them at any time.
--------------
### Notable changes
* Support for the Altair hard fork and the [latest Ethereum consensus spec](https://github.com/ethereum/consensus-specs/releases/tag/v1.1.1) (`v1.1.1`)
* Our [REST API](https://nimbus.guide/rest-api.html) is now feature complete, supporting the full [Beacon API](https://ethereum.github.io/beacon-APIs/) specification. This API should not be exposed to the public Internet as it includes multiple endpoints which could open your node to denial-of-service (DoS) attacks.
* Known limitations: To use the REST API with a validator client, you need to enable the `--subscribe-all-subnets` option. This requirement will be removed in future versions.
* A new experimental `--num-threads=X` option allows Nimbus to take advantage of multiple CPU cores when verifying attestations. Set it to `1` to use one worker thread, `2` for two worker threads, etc. The default value is set to `1` in this release, but future versions will set it to `0` (this tells the client to use as many worker threads as there are CPU cores available). N.B .**enabling anything other than `1` is considered experimental** at this stage.
* Improved peer discovery logic that ensures good connectivity to all gossip subnets.
* A new `version` metric that makes it easy to keep track of client upgrades within Grafana dashboards.
* New metrics `libp2p_peers_identity`, `libp2p_peers_traffic_read_total`, `libp2p_peers_traffic_write_total`, subdivided through Prometheus labels by the client type of the peer (i.e. nimbus, prysm, teku, lodestar or lighthouse).
* BLST has been upgraded to the latest version (`v0.3.5`).
* The `--network` option now accepts a directory with custom network metadata in the format of the [eth2-testnets](https://github.com/eth2-clients/eth2-networks) repository. The `SECONDS_PER_SLOT` configuration value remains the only setting that must be supplied at compile-time through the `-d:SECONDS_PER_SLOT=X` nim compilation flag.
This release is marked as `low-urgency` for all Nimbus users other than those who have recently updated to `v1.4.1` from a version earlier than `v1.1.0` - for these users this is a `high-urgency` release.
## Notable changes
This release fixes an issue in the upgrade procedure when upgrading from a version earlier than `1.1.0` to `1.4.x`.
**How can I tell if I've been affected?**
If you've already upgraded to `1.4.1`, you can tell that you've been affected if you're seeing the following` WRN log`:
```
Received invalid sequence of blocks
```
To re-iterate, this issue only affects users who are upgrading from `1.0.12` or earlier (released on `2021-03-10`), **and have not run any release in between**. Everyone else can ignore this release.
Nimbus `v1.4.0` users might have noticed that they are missing a small number of (seemingly random) attestations since the update. Our investigation into the matter has showed that, due to `v1.4.0`'s significant performance improvements, Nimbus validators occasionally send their first attestation for a new epoch before some peers are ready. These "slow" peers end up dropping early attestations because they're busy with the epoch transition.
It's a rare occurrence, since it requires a validator to be scheduled to attest in the first slot of an epoch *and* for the beacon node to only be connected to "slow" peers for the respective libp2p topic. If both these conditions are true, a premature attestation may be lost in time, like tears in the rain.
As a fix, we are using a larger send delay: [#2705](https://github.com/status-im/nimbus-eth2/pull/2705).
Fo those Nimbus `v1.4.0` users who are concerned about reaching optimal attestation effectiveness, we encourage you to upgrade as soon as possible.
Other changes include log flushing and metrics fixes.
Full list:
- increase attestation wait time ([#2705](https://github.com/status-im/nimbus-eth2/pull/2705))
- ensure logs are printed without delays ([#2669](https://github.com/status-im/nimbus-eth2/pull/2669))
- fix metrics on Windows ([#2707](https://github.com/status-im/nimbus-eth2/pull/2707))
This release is marked as low-urgency - please update at your convenience.
It contains **improvements to attestation effectiveness and CPU usage**.
It also contains **improvements to the RPC APIs**, as suggested by DappNode and RocketPool, and in preparation for our refactored validator client.
### Outdated Nimbus instances
A reminder that if you're running Nimbus with a version prior to `1.0.10` (March 2021) you are exposed to a vulnerability in our core cryptography library (this library is used by all eth2 clients). See this [blst security advisory](https://github.com/supranational/blst/security/advisories/GHSA-x279-68rr-jp4p) for more information. If this concerns you, please update as soon as you can.
## Notable changes
### We've added:
* Nightly builds for the very adventurous. (https://github.com/status-im/nimbus-eth2/pull/2640)
* We expect users of nightly builds to be comfortable providing debugging logs.
### We've fixed:
* RPC API endpoints (https://github.com/status-im/nimbus-eth2/pull/2585, https://github.com/status-im/nimbus-eth2/pull/2586)
*`/eth/v1/beacon/pool/attestations`
*`/api/eth/v1/validator/aggregate_and_proofs`
* Doppelganger detection: fixed false positive on fast restart (https://github.com/status-im/nimbus-eth2/pull/2656/)
### We've improved
* Database read performance improvements during epoch transitions and startup (https://github.com/status-im/nimbus-eth2/pull/2639, https://github.com/status-im/nimbus-eth2/pull/2617)
* Better usage of caches, specially when validating attestations (https://github.com/status-im/nimbus-eth2/pull/2631)
