diff --git a/README.md b/README.md
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--- a/README.md
+++ b/README.md
@@ -1,7 +1,20 @@
 # Blotter.rs
 
-A Rust parser for the Blotter file format.
+Blotter file format parser and Logic World sandbox editor in Rust.
 
-Current version: [Blotter v5][spec]
+## Current version 
 
-[spec]: https://gist.github.com/JimmyCushnie/bebea37a21acbb6e669589967f9512a2
+This is the version that is supported for loading/saving and high-level editing:
+
+- **Blotter v6** (Logic World 0.91 beta)
+    - Not formalized yet, mostly same as v5, but component positions are
+      integers and custom data formats changed for some components
+
+## Legacy versions
+
+There are no high-level APIs for these versions, but converting the savefile to
+newer versions is supported:
+
+- [**Blotter v5**][v5] (Logic World 0.90)
+
+[v5]: https://gist.github.com/JimmyCushnie/bebea37a21acbb6e669589967f9512a2