diff --git a/.gitignore b/.gitignore
index 7c3ead5c..fd43ef01 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,4 +5,5 @@ coverage
 node_modules/
 .DS_Store
 *.local
+*.local.md
 .idea
diff --git a/AGENTS.md b/AGENTS.md
index dc724aa0..06658204 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -4,7 +4,7 @@ This repository is `tailwind-merge`, a TypeScript library that merges Tailwind c
 
 ## Primary Goals
 
-- Keep merge behavior correct for supported Tailwind versions (currently v4.0-v4.1).
+- Keep merge behavior correct for supported Tailwind versions (currently v4.0-v4.2).
 - Keep runtime fast (browser-oriented hot path, lazy init, lightweight cache).
 - Keep API and type contracts stable.
 
diff --git a/docs/README.md b/docs/README.md
index 2c0a284b..27b5cb4f 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -16,7 +16,7 @@ twMerge('px-2 py-1 bg-red hover:bg-dark-red', 'p-3 bg-[#B91C1C]')
 // → 'hover:bg-dark-red p-3 bg-[#B91C1C]'
 ```
 
-- Supports Tailwind v4.0 up to v4.1 (if you use Tailwind v3, use [tailwind-merge v2.6.0](https://github.com/dcastil/tailwind-merge/tree/v2.6.0))
+- Supports Tailwind v4.0 up to v4.2 (if you use Tailwind v3, use [tailwind-merge v2.6.0](https://github.com/dcastil/tailwind-merge/tree/v2.6.0))
 - Works in all modern browsers and maintained Node versions
 - Fully typed
 - [Check bundle size on Bundlephobia](https://bundlephobia.com/package/tailwind-merge)
diff --git a/src/lib/default-config.ts b/src/lib/default-config.ts
index 19c97632..ced00268 100644
--- a/src/lib/default-config.ts
+++ b/src/lib/default-config.ts
@@ -137,6 +137,33 @@ export const getDefaultConfig = () => {
             'fit',
             ...scaleUnambiguousSpacing(),
         ] as const
+    const scaleSizingInline = () =>
+        [
+            isFraction,
+            'screen',
+            'full',
+            'dvw',
+            'lvw',
+            'svw',
+            'min',
+            'max',
+            'fit',
+            ...scaleUnambiguousSpacing(),
+        ] as const
+    const scaleSizingBlock = () =>
+        [
+            isFraction,
+            'screen',
+            'full',
+            'lh',
+            'dvh',
+            'lvh',
+            'svh',
+            'min',
+            'max',
+            'fit',
+            ...scaleUnambiguousSpacing(),
+        ] as const
     const scaleColor = () => [themeColor, isArbitraryVariable, isArbitraryValue] as const
     const scaleBgPosition = () =>
         [
@@ -390,30 +417,60 @@ export const getDefaultConfig = () => {
              */
             position: ['static', 'fixed', 'absolute', 'relative', 'sticky'],
             /**
-             * Top / Right / Bottom / Left
+             * Inset
              * @see https://tailwindcss.com/docs/top-right-bottom-left
              */
             inset: [{ inset: scaleInset() }],
             /**
-             * Right / Left
+             * Inset Inline
              * @see https://tailwindcss.com/docs/top-right-bottom-left
              */
             'inset-x': [{ 'inset-x': scaleInset() }],
             /**
-             * Top / Bottom
+             * Inset Block
              * @see https://tailwindcss.com/docs/top-right-bottom-left
              */
             'inset-y': [{ 'inset-y': scaleInset() }],
             /**
-             * Start
+             * Inset Inline Start
              * @see https://tailwindcss.com/docs/top-right-bottom-left
+             * @todo class group will be renamed to `inset-s` in next major release
              */
-            start: [{ start: scaleInset() }],
+            start: [
+                {
+                    'inset-s': scaleInset(),
+                    /**
+                     * @deprecated since Tailwind CSS v4.2.0 in favor of `inset-s-*` utilities.
+                     * @see https://github.com/tailwindlabs/tailwindcss/pull/19613
+                     */
+                    start: scaleInset(),
+                },
+            ],
+            /**
+             * Inset Inline End
+             * @see https://tailwindcss.com/docs/top-right-bottom-left
+             * @todo class group will be renamed to `inset-e` in next major release
+             */
+            end: [
+                {
+                    'inset-e': scaleInset(),
+                    /**
+                     * @deprecated since Tailwind CSS v4.2.0 in favor of `inset-e-*` utilities.
+                     * @see https://github.com/tailwindlabs/tailwindcss/pull/19613
+                     */
+                    end: scaleInset(),
+                },
+            ],
+            /**
+             * Inset Block Start
+             * @see https://tailwindcss.com/docs/top-right-bottom-left
+             */
+            'inset-bs': [{ 'inset-bs': scaleInset() }],
             /**
-             * End
+             * Inset Block End
              * @see https://tailwindcss.com/docs/top-right-bottom-left
              */
-            end: [{ end: scaleInset() }],
+            'inset-be': [{ 'inset-be': scaleInset() }],
             /**
              * Top
              * @see https://tailwindcss.com/docs/top-right-bottom-left
@@ -629,25 +686,35 @@ export const getDefaultConfig = () => {
              */
             p: [{ p: scaleUnambiguousSpacing() }],
             /**
-             * Padding X
+             * Padding Inline
              * @see https://tailwindcss.com/docs/padding
              */
             px: [{ px: scaleUnambiguousSpacing() }],
             /**
-             * Padding Y
+             * Padding Block
              * @see https://tailwindcss.com/docs/padding
              */
             py: [{ py: scaleUnambiguousSpacing() }],
             /**
-             * Padding Start
+             * Padding Inline Start
              * @see https://tailwindcss.com/docs/padding
              */
             ps: [{ ps: scaleUnambiguousSpacing() }],
             /**
-             * Padding End
+             * Padding Inline End
              * @see https://tailwindcss.com/docs/padding
              */
             pe: [{ pe: scaleUnambiguousSpacing() }],
+            /**
+             * Padding Block Start
+             * @see https://tailwindcss.com/docs/padding
+             */
+            pbs: [{ pbs: scaleUnambiguousSpacing() }],
+            /**
+             * Padding Block End
+             * @see https://tailwindcss.com/docs/padding
+             */
+            pbe: [{ pbe: scaleUnambiguousSpacing() }],
             /**
              * Padding Top
              * @see https://tailwindcss.com/docs/padding
@@ -674,25 +741,35 @@ export const getDefaultConfig = () => {
              */
             m: [{ m: scaleMargin() }],
             /**
-             * Margin X
+             * Margin Inline
              * @see https://tailwindcss.com/docs/margin
              */
             mx: [{ mx: scaleMargin() }],
             /**
-             * Margin Y
+             * Margin Block
              * @see https://tailwindcss.com/docs/margin
              */
             my: [{ my: scaleMargin() }],
             /**
-             * Margin Start
+             * Margin Inline Start
              * @see https://tailwindcss.com/docs/margin
              */
             ms: [{ ms: scaleMargin() }],
             /**
-             * Margin End
+             * Margin Inline End
              * @see https://tailwindcss.com/docs/margin
              */
             me: [{ me: scaleMargin() }],
+            /**
+             * Margin Block Start
+             * @see https://tailwindcss.com/docs/margin
+             */
+            mbs: [{ mbs: scaleMargin() }],
+            /**
+             * Margin Block End
+             * @see https://tailwindcss.com/docs/margin
+             */
+            mbe: [{ mbe: scaleMargin() }],
             /**
              * Margin Top
              * @see https://tailwindcss.com/docs/margin
@@ -743,6 +820,36 @@ export const getDefaultConfig = () => {
              * @see https://tailwindcss.com/docs/width#setting-both-width-and-height
              */
             size: [{ size: scaleSizing() }],
+            /**
+             * Inline Size
+             * @see https://tailwindcss.com/docs/width
+             */
+            'inline-size': [{ inline: ['auto', ...scaleSizingInline()] }],
+            /**
+             * Min-Inline Size
+             * @see https://tailwindcss.com/docs/min-width
+             */
+            'min-inline-size': [{ 'min-inline': ['auto', ...scaleSizingInline()] }],
+            /**
+             * Max-Inline Size
+             * @see https://tailwindcss.com/docs/max-width
+             */
+            'max-inline-size': [{ 'max-inline': ['none', ...scaleSizingInline()] }],
+            /**
+             * Block Size
+             * @see https://tailwindcss.com/docs/height
+             */
+            'block-size': [{ block: ['auto', ...scaleSizingBlock()] }],
+            /**
+             * Min-Block Size
+             * @see https://tailwindcss.com/docs/min-height
+             */
+            'min-block-size': [{ 'min-block': ['auto', ...scaleSizingBlock()] }],
+            /**
+             * Max-Block Size
+             * @see https://tailwindcss.com/docs/max-height
+             */
+            'max-block-size': [{ 'max-block': ['none', ...scaleSizingBlock()] }],
             /**
              * Width
              * @see https://tailwindcss.com/docs/width
@@ -855,6 +962,11 @@ export const getDefaultConfig = () => {
             'font-family': [
                 { font: [isArbitraryVariableFamilyName, isArbitraryFamilyName, themeFont] },
             ],
+            /**
+             * Font Feature Settings
+             * @see https://tailwindcss.com/docs/font-feature-settings
+             */
+            'font-features': [{ 'font-features': [isArbitraryValue] }],
             /**
              * Font Variant Numeric
              * @see https://tailwindcss.com/docs/font-variant-numeric
@@ -1226,25 +1338,35 @@ export const getDefaultConfig = () => {
              */
             'border-w': [{ border: scaleBorderWidth() }],
             /**
-             * Border Width X
+             * Border Width Inline
              * @see https://tailwindcss.com/docs/border-width
              */
             'border-w-x': [{ 'border-x': scaleBorderWidth() }],
             /**
-             * Border Width Y
+             * Border Width Block
              * @see https://tailwindcss.com/docs/border-width
              */
             'border-w-y': [{ 'border-y': scaleBorderWidth() }],
             /**
-             * Border Width Start
+             * Border Width Inline Start
              * @see https://tailwindcss.com/docs/border-width
              */
             'border-w-s': [{ 'border-s': scaleBorderWidth() }],
             /**
-             * Border Width End
+             * Border Width Inline End
              * @see https://tailwindcss.com/docs/border-width
              */
             'border-w-e': [{ 'border-e': scaleBorderWidth() }],
+            /**
+             * Border Width Block Start
+             * @see https://tailwindcss.com/docs/border-width
+             */
+            'border-w-bs': [{ 'border-bs': scaleBorderWidth() }],
+            /**
+             * Border Width Block End
+             * @see https://tailwindcss.com/docs/border-width
+             */
+            'border-w-be': [{ 'border-be': scaleBorderWidth() }],
             /**
              * Border Width Top
              * @see https://tailwindcss.com/docs/border-width
@@ -1301,25 +1423,35 @@ export const getDefaultConfig = () => {
              */
             'border-color': [{ border: scaleColor() }],
             /**
-             * Border Color X
+             * Border Color Inline
              * @see https://tailwindcss.com/docs/border-color
              */
             'border-color-x': [{ 'border-x': scaleColor() }],
             /**
-             * Border Color Y
+             * Border Color Block
              * @see https://tailwindcss.com/docs/border-color
              */
             'border-color-y': [{ 'border-y': scaleColor() }],
             /**
-             * Border Color S
+             * Border Color Inline Start
              * @see https://tailwindcss.com/docs/border-color
              */
             'border-color-s': [{ 'border-s': scaleColor() }],
             /**
-             * Border Color E
+             * Border Color Inline End
              * @see https://tailwindcss.com/docs/border-color
              */
             'border-color-e': [{ 'border-e': scaleColor() }],
+            /**
+             * Border Color Block Start
+             * @see https://tailwindcss.com/docs/border-color
+             */
+            'border-color-bs': [{ 'border-bs': scaleColor() }],
+            /**
+             * Border Color Block End
+             * @see https://tailwindcss.com/docs/border-color
+             */
+            'border-color-be': [{ 'border-be': scaleColor() }],
             /**
              * Border Color Top
              * @see https://tailwindcss.com/docs/border-color
@@ -2055,25 +2187,35 @@ export const getDefaultConfig = () => {
              */
             'scroll-m': [{ 'scroll-m': scaleUnambiguousSpacing() }],
             /**
-             * Scroll Margin X
+             * Scroll Margin Inline
              * @see https://tailwindcss.com/docs/scroll-margin
              */
             'scroll-mx': [{ 'scroll-mx': scaleUnambiguousSpacing() }],
             /**
-             * Scroll Margin Y
+             * Scroll Margin Block
              * @see https://tailwindcss.com/docs/scroll-margin
              */
             'scroll-my': [{ 'scroll-my': scaleUnambiguousSpacing() }],
             /**
-             * Scroll Margin Start
+             * Scroll Margin Inline Start
              * @see https://tailwindcss.com/docs/scroll-margin
              */
             'scroll-ms': [{ 'scroll-ms': scaleUnambiguousSpacing() }],
             /**
-             * Scroll Margin End
+             * Scroll Margin Inline End
              * @see https://tailwindcss.com/docs/scroll-margin
              */
             'scroll-me': [{ 'scroll-me': scaleUnambiguousSpacing() }],
+            /**
+             * Scroll Margin Block Start
+             * @see https://tailwindcss.com/docs/scroll-margin
+             */
+            'scroll-mbs': [{ 'scroll-mbs': scaleUnambiguousSpacing() }],
+            /**
+             * Scroll Margin Block End
+             * @see https://tailwindcss.com/docs/scroll-margin
+             */
+            'scroll-mbe': [{ 'scroll-mbe': scaleUnambiguousSpacing() }],
             /**
              * Scroll Margin Top
              * @see https://tailwindcss.com/docs/scroll-margin
@@ -2100,25 +2242,35 @@ export const getDefaultConfig = () => {
              */
             'scroll-p': [{ 'scroll-p': scaleUnambiguousSpacing() }],
             /**
-             * Scroll Padding X
+             * Scroll Padding Inline
              * @see https://tailwindcss.com/docs/scroll-padding
              */
             'scroll-px': [{ 'scroll-px': scaleUnambiguousSpacing() }],
             /**
-             * Scroll Padding Y
+             * Scroll Padding Block
              * @see https://tailwindcss.com/docs/scroll-padding
              */
             'scroll-py': [{ 'scroll-py': scaleUnambiguousSpacing() }],
             /**
-             * Scroll Padding Start
+             * Scroll Padding Inline Start
              * @see https://tailwindcss.com/docs/scroll-padding
              */
             'scroll-ps': [{ 'scroll-ps': scaleUnambiguousSpacing() }],
             /**
-             * Scroll Padding End
+             * Scroll Padding Inline End
              * @see https://tailwindcss.com/docs/scroll-padding
              */
             'scroll-pe': [{ 'scroll-pe': scaleUnambiguousSpacing() }],
+            /**
+             * Scroll Padding Block Start
+             * @see https://tailwindcss.com/docs/scroll-padding
+             */
+            'scroll-pbs': [{ 'scroll-pbs': scaleUnambiguousSpacing() }],
+            /**
+             * Scroll Padding Block End
+             * @see https://tailwindcss.com/docs/scroll-padding
+             */
+            'scroll-pbe': [{ 'scroll-pbe': scaleUnambiguousSpacing() }],
             /**
              * Scroll Padding Top
              * @see https://tailwindcss.com/docs/scroll-padding
@@ -2243,15 +2395,26 @@ export const getDefaultConfig = () => {
         conflictingClassGroups: {
             overflow: ['overflow-x', 'overflow-y'],
             overscroll: ['overscroll-x', 'overscroll-y'],
-            inset: ['inset-x', 'inset-y', 'start', 'end', 'top', 'right', 'bottom', 'left'],
+            inset: [
+                'inset-x',
+                'inset-y',
+                'inset-bs',
+                'inset-be',
+                'start',
+                'end',
+                'top',
+                'right',
+                'bottom',
+                'left',
+            ],
             'inset-x': ['right', 'left'],
             'inset-y': ['top', 'bottom'],
             flex: ['basis', 'grow', 'shrink'],
             gap: ['gap-x', 'gap-y'],
-            p: ['px', 'py', 'ps', 'pe', 'pt', 'pr', 'pb', 'pl'],
+            p: ['px', 'py', 'ps', 'pe', 'pbs', 'pbe', 'pt', 'pr', 'pb', 'pl'],
             px: ['pr', 'pl'],
             py: ['pt', 'pb'],
-            m: ['mx', 'my', 'ms', 'me', 'mt', 'mr', 'mb', 'ml'],
+            m: ['mx', 'my', 'ms', 'me', 'mbs', 'mbe', 'mt', 'mr', 'mb', 'ml'],
             mx: ['mr', 'ml'],
             my: ['mt', 'mb'],
             size: ['w', 'h'],
@@ -2297,6 +2460,8 @@ export const getDefaultConfig = () => {
                 'border-w-y',
                 'border-w-s',
                 'border-w-e',
+                'border-w-bs',
+                'border-w-be',
                 'border-w-t',
                 'border-w-r',
                 'border-w-b',
@@ -2309,6 +2474,8 @@ export const getDefaultConfig = () => {
                 'border-color-y',
                 'border-color-s',
                 'border-color-e',
+                'border-color-bs',
+                'border-color-be',
                 'border-color-t',
                 'border-color-r',
                 'border-color-b',
@@ -2323,6 +2490,8 @@ export const getDefaultConfig = () => {
                 'scroll-my',
                 'scroll-ms',
                 'scroll-me',
+                'scroll-mbs',
+                'scroll-mbe',
                 'scroll-mt',
                 'scroll-mr',
                 'scroll-mb',
@@ -2335,6 +2504,8 @@ export const getDefaultConfig = () => {
                 'scroll-py',
                 'scroll-ps',
                 'scroll-pe',
+                'scroll-pbs',
+                'scroll-pbe',
                 'scroll-pt',
                 'scroll-pr',
                 'scroll-pb',
diff --git a/src/lib/types.ts b/src/lib/types.ts
index 274c95a0..1cf30f2a 100644
--- a/src/lib/types.ts
+++ b/src/lib/types.ts
@@ -236,9 +236,12 @@ export type DefaultClassGroupIds =
     | 'bg-position'
     | 'bg-repeat'
     | 'bg-size'
+    | 'block-size'
     | 'blur'
     | 'border-collapse'
     | 'border-color-b'
+    | 'border-color-be'
+    | 'border-color-bs'
     | 'border-color-e'
     | 'border-color-l'
     | 'border-color-r'
@@ -252,6 +255,8 @@ export type DefaultClassGroupIds =
     | 'border-spacing'
     | 'border-style'
     | 'border-w-b'
+    | 'border-w-be'
+    | 'border-w-bs'
     | 'border-w-e'
     | 'border-w-l'
     | 'border-w-r'
@@ -301,6 +306,7 @@ export type DefaultClassGroupIds =
     | 'flex'
     | 'float'
     | 'font-family'
+    | 'font-features'
     | 'font-size'
     | 'font-smoothing'
     | 'font-stretch'
@@ -331,10 +337,13 @@ export type DefaultClassGroupIds =
     | 'hue-rotate'
     | 'hyphens'
     | 'indent'
+    | 'inline-size'
     | 'inset-ring-color'
     | 'inset-ring-w'
     | 'inset-shadow-color'
     | 'inset-shadow'
+    | 'inset-be'
+    | 'inset-bs'
     | 'inset-x'
     | 'inset-y'
     | 'inset'
@@ -401,11 +410,17 @@ export type DefaultClassGroupIds =
     | 'mask-repeat'
     | 'mask-size'
     | 'mask-type'
+    | 'max-block-size'
     | 'max-h'
+    | 'max-inline-size'
     | 'max-w'
     | 'mb'
+    | 'mbe'
+    | 'mbs'
     | 'me'
+    | 'min-block-size'
     | 'min-h'
+    | 'min-inline-size'
     | 'min-w'
     | 'mix-blend'
     | 'ml'
@@ -430,6 +445,7 @@ export type DefaultClassGroupIds =
     | 'overscroll'
     | 'p'
     | 'pb'
+    | 'pbe'
     | 'pe'
     | 'perspective-origin'
     | 'perspective'
@@ -442,6 +458,7 @@ export type DefaultClassGroupIds =
     | 'position'
     | 'pr'
     | 'ps'
+    | 'pbs'
     | 'pt'
     | 'px'
     | 'py'
@@ -483,18 +500,22 @@ export type DefaultClassGroupIds =
     | 'scroll-behavior'
     | 'scroll-m'
     | 'scroll-mb'
+    | 'scroll-mbe'
     | 'scroll-me'
     | 'scroll-ml'
     | 'scroll-mr'
+    | 'scroll-mbs'
     | 'scroll-ms'
     | 'scroll-mt'
     | 'scroll-mx'
     | 'scroll-my'
     | 'scroll-p'
     | 'scroll-pb'
+    | 'scroll-pbe'
     | 'scroll-pe'
     | 'scroll-pl'
     | 'scroll-pr'
+    | 'scroll-pbs'
     | 'scroll-ps'
     | 'scroll-pt'
     | 'scroll-px'
diff --git a/src/lib/validators.ts b/src/lib/validators.ts
index ef239539..fd2d9406 100644
--- a/src/lib/validators.ts
+++ b/src/lib/validators.ts
@@ -1,6 +1,6 @@
 const arbitraryValueRegex = /^\[(?:(\w[\w-]*):)?(.+)\]$/i
 const arbitraryVariableRegex = /^\((?:(\w[\w-]*):)?(.+)\)$/i
-const fractionRegex = /^\d+\/\d+$/
+const fractionRegex = /^\d+(?:\.\d+)?\/\d+(?:\.\d+)?$/
 const tshirtUnitRegex = /^(\d+(\.\d+)?)?(xs|sm|md|lg|xl)$/
 const lengthUnitRegex =
     /\d+(%|px|r?em|[sdl]?v([hwib]|min|max)|pt|pc|in|cm|mm|cap|ch|ex|r?lh|cq(w|h|i|b|min|max))|\b(calc|min|max|clamp)\(.+\)|^0$/
diff --git a/tests/class-map.test.ts b/tests/class-map.test.ts
index bfdee9fd..ab0e352f 100644
--- a/tests/class-map.test.ts
+++ b/tests/class-map.test.ts
@@ -49,12 +49,14 @@ test('class map has correct class groups at first part', () => {
             'bg-repeat',
             'bg-size',
         ],
-        block: ['display'],
+        block: ['block-size', 'display'],
         blur: ['blur'],
         border: [
             'border-collapse',
             'border-color',
             'border-color-b',
+            'border-color-be',
+            'border-color-bs',
             'border-color-e',
             'border-color-l',
             'border-color-r',
@@ -68,6 +70,8 @@ test('class map has correct class groups at first part', () => {
             'border-style',
             'border-w',
             'border-w-b',
+            'border-w-be',
+            'border-w-bs',
             'border-w-e',
             'border-w-l',
             'border-w-r',
@@ -114,7 +118,7 @@ test('class map has correct class groups at first part', () => {
         flex: ['display', 'flex', 'flex-direction', 'flex-wrap'],
         float: ['float'],
         flow: ['display'],
-        font: ['font-family', 'font-stretch', 'font-weight'],
+        font: ['font-family', 'font-features', 'font-stretch', 'font-weight'],
         forced: ['forced-color-adjust'],
         from: ['gradient-from', 'gradient-from-pos'],
         gap: ['gap', 'gap-x', 'gap-y'],
@@ -126,15 +130,19 @@ test('class map has correct class groups at first part', () => {
         hue: ['hue-rotate'],
         hyphens: ['hyphens'],
         indent: ['indent'],
-        inline: ['display'],
+        inline: ['display', 'inline-size'],
         inset: [
+            'end',
             'inset',
+            'inset-be',
+            'inset-bs',
             'inset-ring-color',
             'inset-ring-w',
             'inset-shadow',
             'inset-shadow-color',
             'inset-x',
             'inset-y',
+            'start',
         ],
         invert: ['invert'],
         invisible: ['visibility'],
@@ -203,10 +211,12 @@ test('class map has correct class groups at first part', () => {
             'mask-size',
             'mask-type',
         ],
-        max: ['max-h', 'max-w'],
+        max: ['max-block-size', 'max-h', 'max-inline-size', 'max-w'],
         mb: ['mb'],
+        mbe: ['mbe'],
+        mbs: ['mbs'],
         me: ['me'],
-        min: ['min-h', 'min-w'],
+        min: ['min-block-size', 'min-h', 'min-inline-size', 'min-w'],
         mix: ['mix-blend'],
         ml: ['ml'],
         mr: ['mr'],
@@ -229,6 +239,8 @@ test('class map has correct class groups at first part', () => {
         overscroll: ['overscroll', 'overscroll-x', 'overscroll-y'],
         p: ['p'],
         pb: ['pb'],
+        pbe: ['pbe'],
+        pbs: ['pbs'],
         pe: ['pe'],
         perspective: ['perspective', 'perspective-origin'],
         pl: ['pl'],
@@ -271,6 +283,8 @@ test('class map has correct class groups at first part', () => {
             'scroll-behavior',
             'scroll-m',
             'scroll-mb',
+            'scroll-mbe',
+            'scroll-mbs',
             'scroll-me',
             'scroll-ml',
             'scroll-mr',
@@ -280,6 +294,8 @@ test('class map has correct class groups at first part', () => {
             'scroll-my',
             'scroll-p',
             'scroll-pb',
+            'scroll-pbe',
+            'scroll-pbs',
             'scroll-pe',
             'scroll-pl',
             'scroll-pr',
diff --git a/tests/tailwind-css-versions.test.ts b/tests/tailwind-css-versions.test.ts
index 68d0dc98..76d4ccc6 100644
--- a/tests/tailwind-css-versions.test.ts
+++ b/tests/tailwind-css-versions.test.ts
@@ -167,3 +167,128 @@ test('supports Tailwind CSS v4.1.5 features', () => {
     expect(twMerge('min-h-12 min-h-lh')).toBe('min-h-lh')
     expect(twMerge('max-h-12 max-h-lh')).toBe('max-h-lh')
 })
+
+test('supports Tailwind CSS v4.2 features', () => {
+    // Logical inset utilities
+
+    expect(twMerge('inset-s-1 inset-s-2')).toBe('inset-s-2')
+    expect(twMerge('inset-e-1 inset-e-2')).toBe('inset-e-2')
+    expect(twMerge('inset-bs-1 inset-bs-2')).toBe('inset-bs-2')
+    expect(twMerge('inset-be-1 inset-be-2')).toBe('inset-be-2')
+
+    expect(twMerge('start-1 inset-s-2')).toBe('inset-s-2')
+    expect(twMerge('inset-s-1 start-2')).toBe('start-2')
+    expect(twMerge('end-1 inset-e-2')).toBe('inset-e-2')
+    expect(twMerge('inset-e-1 end-2')).toBe('end-2')
+
+    expect(twMerge('inset-s-1 inset-e-2 inset-bs-3 inset-be-4 inset-0')).toBe('inset-0')
+    expect(twMerge('inset-0 inset-s-1 inset-bs-1')).toBe('inset-0 inset-s-1 inset-bs-1')
+
+    expect(twMerge('inset-y-1 inset-bs-2 inset-be-3')).toBe('inset-y-1 inset-bs-2 inset-be-3')
+    expect(twMerge('top-1 inset-bs-2 bottom-3 inset-be-4')).toBe(
+        'top-1 inset-bs-2 bottom-3 inset-be-4',
+    )
+
+    // Logical spacing utilities
+
+    expect(twMerge('pbs-1 pbs-2')).toBe('pbs-2')
+    expect(twMerge('pbe-1 pbe-2')).toBe('pbe-2')
+    expect(twMerge('mbs-1 mbs-2')).toBe('mbs-2')
+    expect(twMerge('mbe-1 mbe-2')).toBe('mbe-2')
+
+    expect(twMerge('pt-1 pbs-2')).toBe('pt-1 pbs-2')
+    expect(twMerge('pb-1 pbe-2')).toBe('pb-1 pbe-2')
+    expect(twMerge('mt-1 mbs-2')).toBe('mt-1 mbs-2')
+    expect(twMerge('mb-1 mbe-2')).toBe('mb-1 mbe-2')
+
+    expect(twMerge('p-0 pbs-1 pbe-1')).toBe('p-0 pbs-1 pbe-1')
+    expect(twMerge('pbs-1 pbe-1 p-0')).toBe('p-0')
+    expect(twMerge('m-0 mbs-1 mbe-1')).toBe('m-0 mbs-1 mbe-1')
+    expect(twMerge('mbs-1 mbe-1 m-0')).toBe('m-0')
+
+    expect(twMerge('py-1 pbs-2 pbe-3')).toBe('py-1 pbs-2 pbe-3')
+    expect(twMerge('my-1 mbs-2 mbe-3')).toBe('my-1 mbs-2 mbe-3')
+
+    // Logical scroll spacing utilities
+
+    expect(twMerge('scroll-pbs-1 scroll-pbs-2')).toBe('scroll-pbs-2')
+    expect(twMerge('scroll-pbe-1 scroll-pbe-2')).toBe('scroll-pbe-2')
+    expect(twMerge('scroll-mbs-1 scroll-mbs-2')).toBe('scroll-mbs-2')
+    expect(twMerge('scroll-mbe-1 scroll-mbe-2')).toBe('scroll-mbe-2')
+
+    expect(twMerge('scroll-pt-1 scroll-pbs-2')).toBe('scroll-pt-1 scroll-pbs-2')
+    expect(twMerge('scroll-pb-1 scroll-pbe-2')).toBe('scroll-pb-1 scroll-pbe-2')
+    expect(twMerge('scroll-mt-1 scroll-mbs-2')).toBe('scroll-mt-1 scroll-mbs-2')
+    expect(twMerge('scroll-mb-1 scroll-mbe-2')).toBe('scroll-mb-1 scroll-mbe-2')
+
+    expect(twMerge('scroll-p-0 scroll-pbs-1 scroll-pbe-1')).toBe(
+        'scroll-p-0 scroll-pbs-1 scroll-pbe-1',
+    )
+    expect(twMerge('scroll-pbs-1 scroll-pbe-1 scroll-p-0')).toBe('scroll-p-0')
+    expect(twMerge('scroll-m-0 scroll-mbs-1 scroll-mbe-1')).toBe(
+        'scroll-m-0 scroll-mbs-1 scroll-mbe-1',
+    )
+    expect(twMerge('scroll-mbs-1 scroll-mbe-1 scroll-m-0')).toBe('scroll-m-0')
+
+    expect(twMerge('scroll-py-1 scroll-pbs-2 scroll-pbe-3')).toBe(
+        'scroll-py-1 scroll-pbs-2 scroll-pbe-3',
+    )
+    expect(twMerge('scroll-my-1 scroll-mbs-2 scroll-mbe-3')).toBe(
+        'scroll-my-1 scroll-mbs-2 scroll-mbe-3',
+    )
+
+    // Logical border block utilities
+
+    expect(twMerge('border-bs-1 border-bs-2')).toBe('border-bs-2')
+    expect(twMerge('border-be-1 border-be-2')).toBe('border-be-2')
+    expect(twMerge('border-bs-red border-bs-blue')).toBe('border-bs-blue')
+    expect(twMerge('border-be-red border-be-blue')).toBe('border-be-blue')
+
+    expect(twMerge('border-2 border-bs-4 border-be-6')).toBe('border-2 border-bs-4 border-be-6')
+    expect(twMerge('border-bs-4 border-be-6 border-2')).toBe('border-2')
+    expect(twMerge('border-red border-bs-blue border-be-green')).toBe(
+        'border-red border-bs-blue border-be-green',
+    )
+    expect(twMerge('border-bs-blue border-be-green border-red')).toBe('border-red')
+
+    expect(twMerge('border-y-2 border-bs-4 border-be-6')).toBe('border-y-2 border-bs-4 border-be-6')
+    expect(twMerge('border-t-2 border-bs-4 border-b-6 border-be-8')).toBe(
+        'border-t-2 border-bs-4 border-b-6 border-be-8',
+    )
+    expect(twMerge('border-y-red border-bs-blue border-be-green')).toBe(
+        'border-y-red border-bs-blue border-be-green',
+    )
+
+    // Logical size utilities
+
+    expect(twMerge('inline-1/2 inline-3/4')).toBe('inline-3/4')
+    expect(twMerge('block-1/2 block-3/4')).toBe('block-3/4')
+    expect(twMerge('min-inline-auto min-inline-full')).toBe('min-inline-full')
+    expect(twMerge('max-inline-none max-inline-10')).toBe('max-inline-10')
+    expect(twMerge('min-block-auto min-block-lh min-block-10')).toBe('min-block-10')
+    expect(twMerge('max-block-none max-block-lh max-block-10')).toBe('max-block-10')
+
+    expect(twMerge('w-10 inline-20')).toBe('w-10 inline-20')
+    expect(twMerge('h-10 block-20')).toBe('h-10 block-20')
+    expect(twMerge('size-10 inline-20 block-30')).toBe('size-10 inline-20 block-30')
+    expect(twMerge('min-w-10 min-inline-20')).toBe('min-w-10 min-inline-20')
+    expect(twMerge('max-h-10 max-block-20')).toBe('max-h-10 max-block-20')
+
+    // Font feature settings utilities
+
+    expect(twMerge('font-features-["smcp"] font-features-["onum"]')).toBe('font-features-["onum"]')
+    expect(twMerge('font-features-[var(--font-features)] font-features-["liga","dlig"]')).toBe(
+        'font-features-["liga","dlig"]',
+    )
+    expect(twMerge('tabular-nums font-features-["smcp"]')).toBe(
+        'tabular-nums font-features-["smcp"]',
+    )
+    expect(twMerge('font-features-["smcp"] normal-nums')).toBe('font-features-["smcp"] normal-nums')
+    expect(twMerge('font-sans font-features-["smcp"]')).toBe('font-sans font-features-["smcp"]')
+
+    // Fractions with decimal numerator/denominator
+
+    expect(twMerge('aspect-8/11 aspect-8.5/11')).toBe('aspect-8.5/11')
+    expect(twMerge('w-8/11 w-8.5/11')).toBe('w-8.5/11')
+    expect(twMerge('inset-1/2 inset-1.25/2.5')).toBe('inset-1.25/2.5')
+})