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+# Breadcrumbs V4
+
+V4 is a complete rewrite of the plugin. As a result:
+
+-   Many long-standing issues are now resolved
+-   Most features have been reimplimented with backwards-compatiable behaviour.
+-   There are also some breaking changes (marked with "⚠️").
+
+## Fundamental Changes
+
+-   Nodes are added to the graph using their full path, not just their basename. This fixes issue: TODO
+-   Implied relationships are customizable per-Hierarchy, not just globally. This resolves: TODO
+
+## Features
+
+Legend:
+
+-   ✅: Already implemented. Working as previously, and possibly better.
+-   ⌚: Working on, still intend to implement.
+-   ❌: Removed, don't plan to implement.
+-   ❔: Undecided for now.
+
+### Graph Builders
+
+Previously referred to as "Alternative Hierarchies", these are the various ways to add edges to the Breadcrumbs graph.
+
+-   ✅ Regular frontmatter links (`up: [[note]]` in YAML)
+-   ✅ Dataview links (`up:: [[note]]`)
+-   ✅ Tag notes
+-   ✅ List notes (previously called "Hierarchy notes")
+-   ✅ Dendron notes
+-   ❔ CSV notes
+-   ❔ Date notes
+-   ❔ Folder notes
+-   ❔ Regex notes
+-   ❔ Traverse notes
+
+### Commands
+
+-   ✅ Create index from note (and copy to clipboard)
+-   ⌚ Write Breadcrumbs to file
+
+### Views
+
+-   ✅ Matrix view
+-   ✅ Grid view
+-   ❌ Trail view (too similar to Grid view)
+-   ✅ Previous Next view
+-   ❌ Visualisations View (far too complicated, never quite worked)
+-   ❔ Juggl view
+-   ❔ Ducks view
+-   ❔ Tree view
+
+### Codeblocks
+
+-   ✅ Implemented
+
+### API
+
+-   ❔ Probably
+
+## Breaking Changes ⚠️
+
+-   The `BC-tag-note` field is now called `BC-tag-note-tag`.
+    -   You will be notified if any notes use the old syntax, so you can change them.
+-   The setting for specifying which notes to treat as List notes (Hierarchy notes) now uses a frontmatter field instead. So whereas previously, you listed all List note names in one setting, now you have to use the `BC-list-note-field` in each of your hierarchy notes.