diff --git a/README.md b/README.md
index b935d5f..dd364f5 100644
--- a/README.md
+++ b/README.md
@@ -23,7 +23,9 @@ The disk drive interface relies on use of the phase lines to read and write one-
 Certain Macs may have a limitation imposed by their ROM on the number of DCDs they support.  
 
 
-### Compatibility Matrix
+### Compatibility
+
+#### Hardware
 
 | Macintosh  | PIC16F1825 | PIC16F1704 |
 | ---------- | ---------- | ---------- |
@@ -53,6 +55,15 @@ Certain Macs may have a limitation imposed by their ROM on the number of DCDs th
 ‡ Requires use of a nonstandard ROM
 
 
+#### System Software
+
+| Version | Compatible? |
+| ------- | ----------- |
+| 6.0.8   | Yes         |
+| 7.1     | Yes         |
+| 7.5     | No          |
+
+
 ## Technical Details
 
 ### MMC Card Format