WCAG 2.1 vs 2.0: Complete Comparison and Upgrade Guide

Organizations already meeting WCAG 2.0 Level AA often ask: "Should we upgrade to WCAG 2.1?" The answer for most is yes. WCAG 2.1, published in June 2018, extends WCAG 2.0 with 17 new success criteria addressing mobile accessibility, low vision needs, and cognitive disabilities—without changing any existing requirements. Understanding the differences between WCAG 2.1 and 2.0 helps organizations plan their upgrade path strategically.

WCAG 2.1 vs 2.0: The Fundamentals

Backward Compatibility

Critical fact: WCAG 2.1 is fully backward compatible with WCAG 2.0.

This means:

Everything that passes WCAG 2.0 also passes WCAG 2.1
The four principles (Perceivable, Operable, Understandable, Robust) remain unchanged
All 61 WCAG 2.0 success criteria remain identical
The three conformance levels (A, AA, AAA) work the same way
Testing methodologies and techniques still apply

What changed: WCAG 2.1 adds 17 new success criteria without modifying existing ones.

The Numbers

WCAG 2.0: 61 success criteria total

Level A: 25 criteria
Level AA: 13 criteria (38 total with A)
Level AAA: 23 criteria (61 total with A and AA)

WCAG 2.1: 78 success criteria total

Level A: 30 criteria (5 new)
Level AA: 20 criteria (7 new)
Level AAA: 28 criteria (5 new)

For WCAG 2.1 Level AA compliance, you need to meet:

All 30 Level A criteria (25 from 2.0 + 5 new)
All 20 Level AA criteria (13 from 2.0 + 7 new)
Total: 50 success criteria

The 17 New Success Criteria in WCAG 2.1

Level A Additions (5 New Criteria)

2.1.4 Character Key Shortcuts (A)

What: If keyboard shortcuts use only letter, punctuation, number, or symbol characters, users can turn them off, remap them, or they're only active when component has focus
Why: Prevents conflicts with assistive technology and speech input
New in 2.1: Yes, addresses voice control and speech input users

2.5.1 Pointer Gestures (A)

What: Multipoint or path-based gestures have single-pointer alternatives
Why: Users with motor disabilities can't perform complex gestures
New in 2.1: Yes, addresses touch and gesture interfaces

2.5.2 Pointer Cancellation (A)

What: Single-pointer functionality completes on up-event, with abort mechanism
Why: Prevents accidental activation from touch
New in 2.1: Yes, improves touch interaction safety

2.5.3 Label in Name (A)

What: Visible text labels are included in accessible names
Why: Voice control users say what they see
New in 2.1: Yes, critical for voice control

2.5.4 Motion Actuation (A)

What: Motion-triggered functionality has UI alternatives and can be disabled
Why: Users can't always shake/tilt devices; prevents accidental triggering
New in 2.1: Yes, addresses device motion and accessibility

Level AA Additions (7 New Criteria)

1.3.4 Orientation (AA)

What: Content functions in both portrait and landscape unless specific orientation essential
Why: Users orient devices based on disability needs or preferences
New in 2.1: Yes, essential for mobile accessibility

1.3.5 Identify Input Purpose (AA)

What: Input purpose can be programmatically determined for common fields
Why: Enables autofill and helps users with cognitive disabilities
New in 2.1: Yes, uses autocomplete attribute

1.4.10 Reflow (AA)

What: Content reflows at 320 CSS pixels width without horizontal scrolling
Why: Low vision users who zoom significantly need single-direction scrolling
New in 2.1: Yes, critical for responsive design and zoom

1.4.11 Non-Text Contrast (AA)

What: UI components and graphics have 3:1 contrast minimum
Why: Low vision and color blind users need to perceive controls
New in 2.1: Yes, extends contrast beyond text

1.4.12 Text Spacing (AA)

What: No loss of content when users override text spacing
Why: Users with dyslexia need customized spacing
New in 2.1: Yes, supports reading disabilities

1.4.13 Content on Hover or Focus (AA)

What: Additional content appearing on hover/focus is dismissible, hoverable, and persistent
Why: Improves tooltip and popup usability
New in 2.1: Yes, addresses dynamic content

4.1.3 Status Messages (AA)

What: Status messages are programmatically determinable by assistive technology
Why: Screen reader users need to know about dynamic updates
New in 2.1: Yes, improves screen reader experience with ARIA live regions

Level AAA Additions (5 New Criteria)

2.2.6 Timeouts (AAA)

What: Users warned about data loss from inactivity
Why: Cognitive disabilities may require more time
New in 2.1: Yes

2.3.3 Animation from Interactions (AAA)

What: Motion animation from interactions can be disabled
Why: Vestibular disorders affected by animation
New in 2.1: Yes

2.5.5 Target Size (AAA)

What: Touch targets are at least 44×44 CSS pixels
Why: Motor disabilities require larger targets
New in 2.1: Yes, widely considered best practice despite AAA level

2.5.6 Concurrent Input Mechanisms (AAA)

What: Content doesn't restrict input modalities
Why: Users switch between keyboard, mouse, touch, voice
New in 2.1: Yes

1.3.6 Identify Purpose (AAA)

What: Purpose of UI components, icons, regions can be programmatically determined
Why: Personalization for cognitive disabilities
New in 2.1: Yes

What Changed vs What's New

What Did NOT Change in WCAG 2.1

No modifications to existing 61 WCAG 2.0 criteria
Same four principles (POUR)
Same conformance model (A, AA, AAA)
Same testing approach (automated + manual + user testing)
Same international standard status (ISO/IEC 40500)

What IS New in WCAG 2.1

Primary focus areas:

Mobile accessibility: Orientation, reflow, touch targets, gestures
Low vision: Non-text contrast, text spacing, reflow
Cognitive disabilities: Input purpose, status messages, timeouts

New technologies addressed:

Touch interfaces and gestures
Voice control and speech input
Responsive design and mobile viewports
Device motion and orientation
ARIA live regions for dynamic content

Comparison Table: WCAG 2.0 vs 2.1 Level AA

| Aspect | WCAG 2.0 AA | WCAG 2.1 AA | Difference | |--------|-------------|-------------|------------| | Total Criteria | 38 | 50 | +12 new | | Mobile Requirements | Implicit | Explicit | 7 mobile-specific criteria | | Touch Gestures | Not addressed | Required alternatives | New 2.5.1 | | Orientation | Not addressed | Must support both | New 1.3.4 | | Reflow/Responsive | Implied by resize text | Explicitly required at 320px | New 1.4.10 | | Non-Text Contrast | Text only | UI components too | New 1.4.11 | | Autocomplete | Not required | Required for common inputs | New 1.3.5 | | Text Spacing | Not addressed | Must support overrides | New 1.4.12 | | Voice Control | Indirectly supported | Explicitly supported | New 2.5.3, 2.1.4 | | Status Messages | Not required | ARIA live regions required | New 4.1.3 |

Upgrading from WCAG 2.0 to 2.1

Step 1: Assess Current State

If you already meet WCAG 2.0 Level AA, you've completed 38 of 50 required criteria for WCAG 2.1 Level AA.

Remaining work: 12 new criteria (5 Level A, 7 Level AA)

Step 2: Prioritize New Criteria by Impact

High priority (affects most sites):

Reflow (1.4.10): Test at 320px width
Non-Text Contrast (1.4.11): Check UI component contrast
Label in Name (2.5.3): Verify accessible names match visible text
Identify Input Purpose (1.3.5): Add autocomplete attributes to forms

Medium priority:

Orientation (1.3.4): Ensure both orientations work
Status Messages (4.1.3): Implement ARIA live regions
Pointer Gestures (2.5.1): Add alternatives to swipe/pinch
Text Spacing (1.4.12): Test with increased spacing

Lower priority (specific use cases):

Pointer Cancellation (2.5.2): Usually met by default
Motion Actuation (2.5.4): Only if you use device motion
Content on Hover/Focus (1.4.13): Only if you have tooltips/dropdowns
Character Key Shortcuts (2.1.4): Only if you have keyboard shortcuts

Step 3: Test Against New Criteria

Reflow testing:

Set browser to 320px width
Or zoom to 400% at 1280px width
Verify no horizontal scrolling

Contrast testing:

Check buttons, form borders, icons with contrast tools
Verify 3:1 minimum against adjacent colors

Mobile testing:

Test on actual mobile devices
Verify both orientations work
Check touch target sizes and gesture alternatives

Form testing:

Add autocomplete attributes (name, email, tel, etc.)
Verify labels match visible text
Test form validation status messages

Step 4: Implement Fixes

Quick wins:

Add autocomplete attributes to forms
Ensure aria-label includes visible text
Make images responsive with max-width: 100%
Fix obvious contrast issues on buttons

Larger efforts:

Implement responsive design for reflow
Add button alternatives to gesture-only interactions
Implement ARIA live regions for status messages
Test and fix text spacing issues

Step 5: Validate and Monitor

Run WCAG 2.1 automated scans
Manual testing against new criteria
User testing with mobile devices and assistive tech
Continuous monitoring to prevent regressions

Should You Target WCAG 2.1 or Stick with 2.0?

Reasons to Upgrade to WCAG 2.1

Better mobile experience: Explicit mobile requirements improve usability

Future-proofing: Regulations increasingly reference WCAG 2.1

European EN 301 549 updated to WCAG 2.1 in 2021
Section 508 (U.S.) likely to update
Some jurisdictions already requiring WCAG 2.1

Improved usability: New criteria benefit all users, not just those with disabilities

Relatively small effort: Only 12 additional criteria if you've met WCAG 2.0 AA

Competitive advantage: Demonstrates commitment to modern accessibility

Reasons Some Organizations Stick with 2.0

Legal requirements reference 2.0: AODA and some regulations explicitly cite WCAG 2.0

Limited resources: Organizations prefer to perfect 2.0 before moving to 2.1

Low mobile traffic: Sites primarily used on desktop may deprioritize mobile criteria

However: Even if legally required to meet only WCAG 2.0, many WCAG 2.1 criteria represent best practices worth adopting.

Migration Strategy

Phased Approach

Phase 1: Mobile foundations

Implement responsive design (reflow)
Fix UI component contrast
Support both orientations

Phase 2: Input improvements

Add form autocomplete
Provide gesture alternatives
Match labels to accessible names

Phase 3: Dynamic content

Implement status message announcements
Fix tooltip and dropdown patterns
Test text spacing overrides

Phase 4: Polish

Address edge cases
Comprehensive testing
Documentation updates

Incremental Implementation

You don't need to address all 12 new criteria simultaneously. Prioritize based on:

User impact: Which criteria affect the most users?
Existing gaps: Where are you farthest from compliance?
Development resources: What fits into current sprints?
Legal requirements: What do regulations in your jurisdiction require?

Testing Tools for WCAG 2.1

Automated scanners supporting WCAG 2.1:

axe DevTools
WAVE (WebAIM)
Lighthouse
BrowseCheck (continuous monitoring)

Manual testing tools:

Color contrast analyzers (check non-text contrast)
Responsive design mode (test reflow)
Browser zoom (test at 400%)
Mobile devices (test orientation and touch)

Assistive technology:

VoiceOver (test status messages)
Voice Control (test label in name)
TalkBack (test mobile accessibility)

Common Upgrade Challenges

Challenge 1: Reflow on Complex Layouts

Legacy desktop-first designs struggle at 320px width.

Solution: Refactor to mobile-first responsive design incrementally, starting with high-traffic pages.

Challenge 2: Non-Text Contrast

Subtle, low-contrast UI that passed 2.0 fails 2.1.

Solution: Review brand guidelines, create accessible component library with adequate contrast.

Challenge 3: Gesture-Dependent Interactions

Image galleries and maps rely only on swipe/pinch.

Solution: Add button controls as alternatives to gestures.

Challenge 4: Inconsistent Labels

Visible text doesn't match aria-labels.

Solution: Audit all components, align accessible names with visible labels.

Conclusion

WCAG 2.1 extends WCAG 2.0 with 17 new success criteria focused on mobile accessibility, low vision needs, and cognitive disabilities. For organizations meeting WCAG 2.0 Level AA, upgrading to WCAG 2.1 Level AA means addressing 12 additional criteria—a manageable effort that delivers significant benefits.

Key differences:

WCAG 2.1 adds 17 new criteria without changing existing 61
Mobile accessibility explicitly addressed (orientation, reflow, touch)
Low vision support enhanced (non-text contrast, text spacing)
Cognitive needs better supported (input purpose, status messages)
Full backward compatibility maintained

Upgrade priorities:

Reflow at 320px width
Non-text contrast for UI components
Autocomplete on form inputs
Accessible names matching visible labels
Both portrait and landscape support

While some regulations still reference WCAG 2.0, forward-thinking organizations are adopting WCAG 2.1 for better mobile experiences, future regulatory compliance, and improved usability for all users.

Ready to upgrade from WCAG 2.0 to 2.1? Start by testing your site at 320px width, checking UI component contrast, and adding autocomplete to forms. These foundational improvements address three of the most common WCAG 2.1 gaps and deliver immediate benefits for mobile and low vision users.

Continuous monitoring tools like BrowseCheck help track both WCAG 2.0 and 2.1 compliance, alerting teams when issues arise and ensuring your accessibility improvements persist as your site evolves.