Improved release note

Author: rijnb

README.md

@@ -48,10 +48,13 @@ decode Mapcodes.
 
 * 1.50
 
+    Major release. This version is not backwards compatible with mapcode 1.4x: is has dropped support for
+    Antartica AT0-8 codes and has a changed (improved) way of dealing with the Greek alphabet.
 
-    Major release. This version is not compatible with mapcode 1.4x!
     Added 22-chararcter post-processing of all-digit mapcodes for the Greek alphabet.
+
     Retired legacy aliases EAZ and SKM, AU-QL, AU-TS, AU-NI and AU-JB.
+
     Retired legacy Antarctica claims AT0 through AT8.
 
 * 1.41.1