## Software

Pages read on 2026-10-27 (UTC). Scope: public software releases, not a measurement of the binaries deployed by Base's sequencer.

L2BEAT describes Base as an optimistic rollup built with the OP Stack, but its current state-validation section describes AggregateVerifier with TEE and SP1 ZK proof arms, rather than assuming the original Cannon setup. [L2BEAT](https://l2beat.com/layer2s/projects/base#state-validation)

The current operator clients are **base-reth-node** (execution) and **base-consensus** (consensus), maintained in Base's [base/base repository](https://github.com/base/base). Base's upgrade guide says only these clients support Azul and tells operators to migrate from op-node, op-geth, op-reth, Nethermind or Kona. This is Base-specific software, not simply the current upstream OP Stack node distribution. [Base node upgrade guide](https://docs.base.org/upgrades/azul/node-upgrade)

The execution software uses Base's Reth fork: the released source pins Reth dependencies to `base-v2.5.2.8` ([released Cargo.toml](https://github.com/base/base/blob/v1.5.1/Cargo.toml)). The operator distribution moved from base/node to base/base beginning with `v1.3.0` ([Run a Node](https://docs.base.org/specifications/node-operators/run-a-node)); the former repository is now archived. [base/node](https://github.com/base/node)

## Newest node release

**Current Base distribution:** repository [base/base](https://github.com/base/base). Tag and release title: `v1.5.1` ([release](https://github.com/base/base/releases/tag/v1.5.1)). Published date shown: **22 Oct 17:47**, with page timestamp **2026-10-22T17:47:20Z** ([release](https://github.com/base/base/releases/tag/v1.5.1)). Marked **Latest**, not pre-release; public, non-draft release. Changes: adds Denim mainnet support to both clients, improves transaction-pool performance and NAT peer discovery, and changes batcher throttling units. [Release notes](https://github.com/base/base/releases/tag/v1.5.1)

The [Releases page](https://github.com/base/base/releases) starts with that stable release. The [Tags page](https://github.com/base/base/tags) instead starts with `v1.5.2-rc.5` ([tag view](https://github.com/base/base/releases/tag/v1.5.2-rc.5)): this is a newer **RC tag**, not a published GitHub release; its page says “tagged this,” not “released this.” No release publication date or pre-release flag is available for that tag. [Release API lookup (404)](https://api.github.com/repos/base/base/releases/tags/v1.5.2-rc.5)

Candidate-repository cross-checks (each Releases page and Tags page opened):

- **Archived distribution:** [base/node](https://github.com/base/node); [Releases](https://github.com/base/node/releases), [Tags](https://github.com/base/node/tags). Top stable tag/title: `v1.2.0` ([release](https://github.com/base/node/releases/tag/v1.2.0)). Published **22 Jul 19:00**, timestamp **2026-07-22T19:00:12Z** ([release](https://github.com/base/node/releases/tag/v1.2.0)). Latest; not pre-release. Notes introduce Reth V2 snapshots/storage migration and fix pruned consensus sync. This is the last release in the archived repository, not the newest current Base client release. [Notes](https://github.com/base/node/releases/tag/v1.2.0)
- **Upstream consensus candidate:** [ethereum-optimism/optimism](https://github.com/ethereum-optimism/optimism); [Releases](https://github.com/ethereum-optimism/optimism/releases), [Tags](https://github.com/ethereum-optimism/optimism/tags). The first stable repository-wide release is actually `op-challenger/v1.11.0`, title “op-challenger v1.11.0” ([release](https://github.com/ethereum-optimism/optimism/releases/tag/op-challenger%2Fv1.11.0)); published **26 Oct 19:49**, timestamp **2026-10-26T19:49:27Z** ([release](https://github.com/ethereum-optimism/optimism/releases/tag/op-challenger%2Fv1.11.0)); not pre-release. Notes fix resolved-game progress accounting, logging and CLI output and update bundled Kona. The newest **op-node-specific** release is tag `op-node/v1.19.11`, title “op-node v1.19.11” ([release](https://github.com/ethereum-optimism/optimism/releases/tag/op-node%2Fv1.19.11)); published **22 Oct 02:51**, timestamp **2026-10-22T02:51:39Z** ([release](https://github.com/ethereum-optimism/optimism/releases/tag/op-node%2Fv1.19.11)); Latest, not pre-release. Notes cover CA/Go security fixes, sequencer L1-origin progress, beacon slot-duration compatibility and startup with pruned L1 history. [Notes](https://github.com/ethereum-optimism/optimism/releases/tag/op-node%2Fv1.19.11) The top tag is instead `op-dispute-mon/v1.6.4-rc.1` ([Tags](https://github.com/ethereum-optimism/optimism/tags)); this is another component's RC, not the node release. These upstream releases do not establish Base operator compatibility. [Base migration guide](https://docs.base.org/upgrades/azul/node-upgrade)
- **Upstream execution candidate:** [ethereum-optimism/op-geth](https://github.com/ethereum-optimism/op-geth); [Releases](https://github.com/ethereum-optimism/op-geth/releases), [Tags](https://github.com/ethereum-optimism/op-geth/tags). Top stable tag/title `v1.101702.3` ([release](https://github.com/ethereum-optimism/op-geth/releases/tag/v1.101702.3)); published **31 Aug 12:30**, timestamp **2026-08-31T12:30:36Z** ([release](https://github.com/ethereum-optimism/op-geth/releases/tag/v1.101702.3)); Latest, not pre-release. Notes add Pion STUN/DTLS security updates and maintenance changes, and explicitly say this is a **library-only release**, op-geth is deprecated and running it is unsupported. [Notes](https://github.com/ethereum-optimism/op-geth/releases/tag/v1.101702.3) Newest tag `v1.101702.4-rc.1` ([Tags](https://github.com/ethereum-optimism/op-geth/tags)) is an RC tag without a published release. [Release API lookup (404)](https://api.github.com/repos/ethereum-optimism/op-geth/releases/tags/v1.101702.4-rc.1)
- **Reth fork candidate:** [base/reth](https://github.com/base/reth); [Releases](https://github.com/base/reth/releases) says there are no releases. The [Tags page](https://github.com/base/reth/tags) starts with `base-v2.8.0.2` ([tag view](https://github.com/base/reth/releases/tag/base-v2.8.0.2)). This is a source tag, not a release with a title, publication date, notes or pre-release flag. Do not substitute its commit date for a release date.

## Newest prover release

**Base proof services: same repository as node**, [base/base](https://github.com/base/base). Its released workspace contains Base proof, challenger, ZK backend, prover-service and Nitro host/enclave code. [Released workspace](https://github.com/base/base/blob/v1.5.1/Cargo.toml) Base documents an SP1 ZK prover service and a TEE prover with `base-prover-nitro-host` and `base-prover-nitro-enclave` binaries. [ZK prover](https://docs.base.org/specifications/base-protocol/proofs/zk-prover), [TEE prover](https://docs.base.org/specifications/base-protocol/proofs/tee-prover)

Newest stable repository tag/title is `v1.5.1` ([release](https://github.com/base/base/releases/tag/v1.5.1)), published **22 Oct 17:47**, timestamp **2026-10-22T17:47:20Z** ([release](https://github.com/base/base/releases/tag/v1.5.1)); not pre-release. The notes describe node/consensus/batcher changes, with no separately identified prover change or separately versioned prover release. [Notes](https://github.com/base/base/releases/tag/v1.5.1) This identifies the latest public source release containing proof services, not the version currently deployed by Base's proof operators.

**Separate upstream proving engine:** Succinct's [succinctlabs/sp1](https://github.com/succinctlabs/sp1), used by Base's documented ZK proof service. [Base ZK prover specification](https://docs.base.org/specifications/base-protocol/proofs/zk-prover) Both [Releases](https://github.com/succinctlabs/sp1/releases) and [Tags](https://github.com/succinctlabs/sp1/tags) start with tag/title `v6.10.0` ([release](https://github.com/succinctlabs/sp1/releases/tag/v6.10.0)). Published **23 Oct 15:31**, timestamp **2026-10-23T15:31:08Z** ([release](https://github.com/succinctlabs/sp1/releases/tag/v6.10.0)); Latest, not pre-release. Notes include a breaking Tonic SDK upgrade and an x86 JIT remainder bug fix. [Notes](https://github.com/succinctlabs/sp1/releases/tag/v6.10.0) This is the newest upstream release, not evidence that Base has deployed it.

## Operator docs version

The current [Run a Node guide](https://docs.base.org/specifications/node-operators/run-a-node) directs operators to base/base and defaults to `ghcr.io/base/node:latest`; it gives `NODE_TAG=v1.3.0 docker compose up` ([guide](https://docs.base.org/specifications/node-operators/run-a-node)) as an example of pinning a published image, not a statement that this is today's newest or required version. It also permits building the current source tree. The [Azul migration guide](https://docs.base.org/upgrades/azul/node-upgrade) explicitly requires the Base-specific execution/consensus clients and tells operators to update to the latest version.

The current release instructions require mainnet operators to upgrade to `v1.5.1` ([release](https://github.com/base/base/releases/tag/v1.5.1)) for Denim by **November 5 at 18:00:00 UTC** ([release instructions](https://github.com/base/base/releases/tag/v1.5.1)). The [Denim docs overview](https://docs.base.org/upgrades/denim/overview) itself lists mainnet as planning and does not pin a software version. These are distinct observations: a moving `latest` default, an illustrative older pin, and the latest release's explicit upgrade instruction.

## Not found

- No public GitHub Release in [base/reth Releases](https://github.com/base/reth/releases); [Tags](https://github.com/base/reth/tags) provides source tags only. Release title, published date, release notes and pre-release status are unavailable there.
- No separately versioned Base prover release or prover-specific change identified in [base/base Releases](https://github.com/base/base/releases), [Tags](https://github.com/base/base/tags), the [stable release notes](https://github.com/base/base/releases/tag/v1.5.1), or the [ZK](https://docs.base.org/specifications/base-protocol/proofs/zk-prover) / [TEE](https://docs.base.org/specifications/base-protocol/proofs/tee-prover) specifications. Public source is available in the node repository; absence of a separate release does not mean closed source.
- The exact currently deployed node/prover binary versions and whether Base uses the newest upstream SP1 release were not established by those pages. Public release recency is not deployment evidence.
- Tags pages initially failed in the web reader; all candidate Tags pages and the additional base/base and SP1 Tags pages were successfully opened directly over HTTPS. RC-only tags were not promoted to stable releases or assigned release publication dates.