Foundations

WCAG Versions Explained: 2.0 vs 2.1 vs 2.2 vs 3.0

WCAG isn't one fixed document — it's been revised three times since the W3C first published it, and a fourth, structurally different version is in early draft. Each revision adds new success criteria on top of the previous version rather than replacing it, so "WCAG 2.2 AA" means "everything in 2.0 AA, plus everything added in 2.1 AA, plus what's new in 2.2 AA."

WCAG 2.0 (2008)

The original version, and still the one most older laws cite by name (including the original EU Web Accessibility Directive and many US state procurement rules). It defined the four POUR principles and the A/AA/AAA conformance levels that every later version has kept. 61 success criteria at Level A and AA combined.

WCAG 2.1 (2018)

Added 17 new success criteria, mostly targeting three groups the 2.0 baseline under-served: mobile users (reflow, orientation, pointer gestures), people with low vision (non-text contrast, text spacing), and people with cognitive or learning disabilities (identify input purpose). This is the version most current legislation references — including the EU's 2025 European Accessibility Act and the US ADA Title II rule for state and local governments.

WCAG 2.2 (October 2023)

Added 9 more success criteria (6 at A/AA, 3 at AAA-only) and — notably — removed one: 4.1.1 Parsing, which existed to catch malformed HTML, is now considered automatically satisfied by modern browsers' error-recovery parsing and was dropped entirely. The AA-level additions worth knowing:

SC	Name	What it requires
2.4.11	Focus Not Obscured (Minimum)	A keyboard-focused element can't be completely hidden behind a sticky header or cookie banner
2.5.7	Dragging Movements	Any drag-based interaction needs a single-click/tap alternative
2.5.8	Target Size (Minimum)	Clickable targets are at least 24×24 CSS pixels, or adequately spaced
3.2.6	Consistent Help	Help mechanisms (contact links, chat widgets) appear in the same relative place across pages
3.3.7	Redundant Entry	Information a user already entered doesn't have to be re-typed
3.3.8	Accessible Authentication (Minimum)	Login can't require solving a cognitive puzzle (like transcribing a CAPTCHA) with no alternative

WCAG 2.2 is the version AllyProof scans against, because it's the most complete supported standard and satisfies every earlier version's requirements by definition.

WCAG 3.0 (draft — not yet a standard)

W3C is developing a successor with a fundamentally different structure: instead of pass/fail success criteria, it proposes a graded scoring model ("Bronze/Silver/Gold") across broader outcome statements. It's still an early public working draft with no fixed publication date, and no law or standard references it yet. Nothing changes for compliance purposes until it actually ships — treat "WCAG 3.0" mentions today as forward-looking, not actionable.

Which version should you actually target?

WCAG 2.2 AA. It's a strict superset of 2.0 and 2.1, so meeting it satisfies every older legal reference too, and it's the version least likely to need a re-audit when the next law updates its citation. See Is WCAG a Law? for how each version maps to specific legal requirements.

Common questions

What is the difference between WCAG 2.0, 2.1, and 2.2?

Each version is additive. 2.1 added criteria (many for mobile and low vision) on top of 2.0, and 2.2 added more (such as focus appearance and dragging alternatives) on top of 2.1. Older criteria carry forward.

Which WCAG version should I comply with?

WCAG 2.1 AA is the most widely referenced legal baseline, and 2.2 AA is the current best target since it is a superset. Meeting 2.2 AA means you also meet 2.1 and 2.0 AA.

What is WCAG 3.0?

An early-draft, structurally different future standard with a new scoring model. It is years from being a compliance requirement, so 2.1 and 2.2 AA remain the practical targets today.