Claude Opus Versions: Release History and What Changed

The Claude Opus versions run from Claude 3 Opus (March 2024) through Opus 4, 4.1, 4.5, 4.6, and 4.7 to today's flagship, Claude Opus 4.8, released May 28, 2026. Opus is Anthropic's top reasoning tier, and every version improved coding and agentic reliability at the same $5/$25 price, so the newest is usually the best pick.

We've shipped this entire site through Claude Opus and re-tested every release the day it landed, so we track the tier closely. This guide is a plain-English tour of the Claude Opus versions: what each release changed, which one is the current flagship, how Anthropic's version numbers work, and how to stay on the latest Claude Opus without babysitting announcement pages. Think of it as the Claude Opus versions explained in a single scan — a practical Claude Opus release history rather than a spec dump.

The Claude Opus versions, oldest to newest

Opus sits at the top of Anthropic's three-tier lineup: Haiku for speed, Sonnet for balance, Opus for the hardest reasoning. The tier has shipped seven numbered releases so far. Here are the Claude Opus versions in order, with ship dates and the headline change each one brought:

What the Claude Opus versions reveal is a tier that changes shape twice over. First, Opus is older than the current numbering suggests: before Claude Opus 4, the only Opus was Claude 3 Opus, and the tier sat out the entire Claude 3.5 and 3.7 era — those releases were Sonnet and Haiku, so for well over a year "Opus" meant a single 2024 model. The wider lineage runs back further still, to Claude 1 and Claude 2 in 2023, before Anthropic split the family into Opus, Sonnet, and Haiku with Claude 3. Second, the jumps are uneven. Claude 3 Opus to Opus 4 was a full rebuild for agentic work; every 4.x step since has been a steady, same-price refinement. We unpack how that cadence plays out across all three tiers in Claude Models Explained.

The current flagship: Claude Opus 4.8

The current flagship is Claude Opus 4.8, which Anthropic shipped on May 28 under the API id claude-opus-4-8. It holds the tier's long-standing pricing — $5 per million input tokens and $25 per million output tokens — alongside a 1M-token context window and 128K maximum output. You get it as the default Opus across claude.ai (Pro, Max, Team, and Enterprise), the Claude API, Claude Code, and the AWS, Google Cloud, and Microsoft Foundry clouds.

Under the hood, Opus 4.8 leans harder into agentic coding than any Opus before it. It uses adaptive thinking — the model decides per turn whether a problem needs reasoning — with an effort parameter that now defaults to high. A new fast mode, in research preview on the API, trades money for speed: up to 2.5× the output tokens per second at premium pricing. For most teams, though, the headline is simpler. It's the strongest Opus, and it costs exactly what 4.6 and 4.7 did.

Claude Opus 4.8 vs 4.7: what actually changed

Opus 4.7 shipped first — the Claude Opus 4.7 release date was April 16, 2026 — and Opus 4.8 followed six weeks later. The gap between them is narrow on paper but real inside agent workflows:

The biggest measured gain is coding. On SWE-bench Pro — the harder of the two agentic-coding benchmarks — Opus 4.8 jumps to 69.2% from 64.3%, a bigger leap than the modest SWE-bench Verified move from 87.6% to 88.6%. Beyond the numbers, Anthropic targeted three behaviors that tripped up 4.7 users: skipped tool calls (the model now triggers required tools more reliably), derailments after context compaction, and inconsistent reasoning at each effort level. Because the price is identical, the practical verdict is that most Opus users should upgrade — a modest but tangible improvement that costs nothing extra.

Why the Opus version matters for coding

For everyday prompts, the gap between recent Claude Opus versions is easy to miss. It shows up in long, tool-heavy coding sessions, where small reasoning errors compound over dozens of steps. That is exactly what SWE-bench Pro measures, and it is where the 4.7-to-4.8 difference widens. If an agent runs for thirty minutes across a dozen files, the newer version drifts less and finishes more of what you actually asked for.

Context helps here too. Every Opus release from 4.6 onward carries a 1M-token window — enough to hold a mid-sized repository and its docs in a single request, which is how we run cross-file refactors on this site; our Claude context window explained guide covers what that ceiling means in practice. And if the real question is whether you need Opus at all versus the cheaper, faster Sonnet tier, that trade-off has its own head-to-head in Claude Sonnet vs Opus. The short version: default to Sonnet, then escalate to the latest Opus when a task measurably needs it.

How Anthropic names and versions Opus models

All the Claude Opus versions share one naming scheme, and decoding it removes most of the confusion. An API string like claude-opus-4-8 reads family-tier-version: claude is the family, opus is the tier, and 4-8 is the version number with a dash standing in for the dot — so, Opus 4.8. Production model ids also carry a snapshot date on the end, which always returns the exact same model.

Two rules follow. First, version numbers only compare within a tier: Opus 4.8 is a far bigger model than Sonnet 5 despite the higher-looking Sonnet number, because they are different sizes that happen to share a numbering scheme. Second, the bare opus alias is provider-dependent and tends to lag behind the newest release:

Because that alias can silently point at an older model depending on where you call it, pin the full dated model id in anything you need to reproduce. Anthropic's own models overview is the canonical list of current ids and prices.

How to always find the latest Claude Opus

Staying current with the Claude Opus versions takes almost no effort once you build two habits:

1. Check the models overview, not the news. The official docs page always lists the current Opus id, context window, and price. Blog roundups go stale within weeks; the docs do not.
2. Pin snapshots, upgrade deliberately. Run production on a dated model id so behavior cannot shift under you, then re-test against the newest Opus when it lands and cut over on your own schedule.

Because Opus pricing has held at $5/$25 across 4.6, 4.7, and 4.8, upgrading is almost always a pure win: you gain coding and agentic reliability at the same rate. We keep our own token-cost math in Anthropic Claude API pricing and the plan-by-plan breakdown in How much does Claude cost.

Above Opus: the new Mythos-class tier

One caveat keeps the "newest Opus is the best model" rule honest. As of June 2026, Opus is no longer Anthropic's absolute ceiling: a new Mythos-class tier — Claude Fable 5, plus a restricted Claude Mythos 5 — now sits above all the Claude Opus versions for the most demanding reasoning and long-horizon agentic work. For the vast majority of coding and knowledge work, though, Claude Opus 4.8 remains the practical flagship and the version most teams should reach for first.

The quick version:

• Claude 3 Opus was the first frontier Opus
• The 4.x line brought big agentic and coding gains
• Opus 4.8 is the current flagship
• It leads SWE-bench Pro at 69.2%

Claude pricing at a glance

For the full breakdown of every plan, see our how much Claude costs guide.