What's new in Mermaid Studio 2026.3.6?

Mermaid Studio 2026.3.6 moves the default bundled Mermaid.js runtime to 11.16.1 and rounds out TreeView icon() annotations with completion and validation.

Highlights

Mermaid 11.16.1

The default Mermaid.js rendering version moves from 11.16.0 to 11.16.1. The other bundled versions (11.15.0, 11.14.0, 11.13.0, and 11.12.3) are unchanged.

Going forward, you can expect the oldest minor version of Mermaid.js to be dropped each time we bundle a new minor version. Patch versions replace older versions within the same minor version.

Keeping the number of supported Mermaid.js versions bounded will prevent the plugin size from becoming bloated and will make it possible to clean up old version-specific behaviors over time.

TreeView icons

Mermaid 11.16.0 gave TreeView diagrams icon() annotations, and prior Mermaid Studio releases only had partial support for this syntax. This release fixes handling for prefixed icon names and adds intelligent icon name completions and validation.

Completion inside the parentheses offers the built-in folder and file icons plus every icon from your enabled icon sets as pack:name references, each with an icon preview. Typing a pack prefix such as logos: filters the list to that pack, as in the capture below.

When the frontmatter sets config.treeView.defaultIconPack, that pack’s icons also complete as bare names, matching how Mermaid resolves an unprefixed name through the default pack. The defaultIconPack, filenameIcons, and extensionIcons keys themselves now get completion and validation in the frontmatter block; see the Mermaid TreeView documentation for what each key does.

A new inspection flags an icon() reference that resolves to no built-in, default-pack, or enabled icon-set icon, since a reference that resolves to nothing renders no icon.

Changelog

Added

• TreeView diagrams: icon-name completion inside icon(...), offering the built-in icons and all enabled icon packs, filtered to the pack after pack:; icons from the frontmatter’s defaultIconPack complete as bare names, typing : or ( opens the popup automatically, and icon( pairs its closing parenthesis
• TreeView diagrams: inspection flagging icon() references that resolve to no built-in, default-pack, or enabled icon-set icon and so would not render
• TreeView diagrams: frontmatter completion and validation for the iconify config keys defaultIconPack, filenameIcons, and extensionIcons

Changed

• Bundled Mermaid 11.16.1 as the default Mermaid.js runtime version, replacing 11.16.0
• Improved icon-name completion performance (architecture, sequence, flowchart, TreeView)

Fixed

• Runtime config overrides: saving the overrides editor (Cmd+S/Ctrl+S) now updates open previews immediately instead of only taking effect when the editor tab is closed
• cynefin, eventmodeling, ishikawa, railroad, swimlane, and venn config sections are no longer flagged as unknown keys, and a few other one-off missing keys are now completed
• TreeView diagrams: icon(pack:name) iconify references (e.g. icon(logos:react)) are accepted, matching Mermaid, instead of being flagged as syntax errors
• Architecture diagrams: completing an icon with the caret inside an existing pack:name reference replaces the whole reference instead of leaving fragments of the old one