The difference between Web Content Accessibility Guidelines (WCAG) 2.1 AA and WCAG 2.2 AA for scans is minimal. WCAG 2.2 builds on 2.1, and the additions in 2.2 are largely outside what automated scans can detect. Most scans that check against 2.1 AA criteria will produce similar results when configured for 2.2 AA.
| Key Point | What It Means |
|---|---|
| Backward Compatibility | WCAG 2.2 includes all 2.1 AA criteria, so a 2.2 AA scan covers everything a 2.1 AA scan does. |
| New Criteria in 2.2 | The criteria added in WCAG 2.2 focus on areas like focus appearance, dragging movements, and consistent help, which are difficult for scans to evaluate. |
| Scan Coverage | Scans detect approximately 25% of WCAG issues regardless of version. The version change does not significantly shift that percentage. |
| Practical Impact | Switching a scan from 2.1 AA to 2.2 AA will not reveal a substantially different set of flagged issues. |
How WCAG 2.2 Relates to WCAG 2.1
WCAG 2.2 is not a replacement for 2.1. It is an extension. Every success criterion in 2.1 AA carries forward into 2.2 AA, with a small number of new criteria added on top.
This backward compatibility means any content that conforms to WCAG 2.2 AA also conforms to 2.1 AA. For organizations running scans, this structure matters because the foundational checks remain identical across both versions.
What Do WCAG 2.1 vs 2.2 Scans Actually Check?
Automated scans evaluate HTML, CSS, and ARIA attributes against a defined set of rules. These rules map to specific WCAG success criteria. The criteria that scans can reliably flag, such as missing alternative text, form label associations, and language declarations, exist in both 2.1 AA and 2.2 AA.
The new criteria introduced in 2.2 address interaction patterns and visual behaviors that require human judgment to evaluate. A scan cannot determine whether a dragging interaction has a single-pointer alternative, or whether help mechanisms appear in a consistent location across pages. These require a person reviewing the interface.
Does the Version Setting on a Scan Tool Matter?
Some scanning configurations let you select a target WCAG version. Selecting 2.2 AA instead of 2.1 AA may add a small number of additional automated checks where partial detection is possible. In most cases, the scan output will look nearly the same.
The version setting is more relevant for reporting purposes. If your organization references WCAG 2.2 AA as its conformance target, configuring scans to report against that version keeps documentation consistent.
Where the Real Difference Shows Up
The meaningful difference between 2.1 AA and 2.2 AA conformance is identified through audits, not scans. An audit conducted by an accessibility professional evaluates the full set of criteria, including the new ones in 2.2 that scans cannot assess.
Scans remain a useful monitoring layer under either version, though scans only flag approximately 25% of issues. They catch regressions, surface code-level problems, and provide ongoing visibility into a site’s accessibility status. The version difference does not change that role.
For organizations moving from a 2.1 AA target to 2.2 AA, the scan configuration is a small administrative update. The larger effort is in the manual evaluation of the new criteria that sit outside automated detection.