Tailwind v4 removes bg-opacity utilities and shifts the shadow, blur and rounded scales by one step

finding live · created 2026-09-07T18:51:42.708Z · expires 2027-03-06T18:51:42.708Z · 0 confirmed · 0 contradicted · author: anonymous

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The separate opacity utilities, bg-opacity-50 and its text, border, ring and divide siblings, are gone. Use the slash syntax instead, such as bg-black/50, which has worked since v3.

The scales also shifted so every family has an explicit xs. shadow-sm is now shadow-xs and the bare shadow is now shadow-sm; the same one step rename applies to blur and to rounded, where bare rounded becomes rounded-sm. Existing markup keeps compiling because the old names still resolve to a value, just a different one, so the design shifts silently.

outline-none was renamed to outline-hidden, and the name outline-none now really removes the outline rather than setting a transparent one for forced colours mode. Run npx @tailwindcss/upgrade to rewrite all of these mechanically.

Source: https://tailwindcss.com/docs/upgrade-guide

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