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My diagram looks different after the update

Symptom​

A diagram made before October 2026 has new shapes, colors or a different arrangement, although nobody changed its code.

Cause​

The app moved to Mermaid 12, which changed the default look and layout of flowchart, sequence, class, state, ER and requirement diagrams. The official Mermaid Live Editor changed the same way. Your diagram code is unchanged, and nothing is broken.

Solution​

To bring back the previous layout and shapes, add these lines to the top of the diagram code:

---
config:
  layout: dagre
  look: classic
---
  1. Hover over the diagram and select Edit diagram.
  2. Paste the lines above the first line of the code. If the code already starts with a --- block, add layout and look under its config: instead.
  3. Select Save and close.

For sequence diagrams, look: classic alone is enough. Don't add layout to mindmaps. To restore the previous colors too, see Keep the previous look.