Update README.md

adjusted mac VNC details

README.md

@@ -15,8 +15,10 @@ Windows](https://bintray.com/tigervnc/stable/download_file?file_path=vncviewer-1
 or as a package from your GNU/Linux distribution. 
 For Mac users, 
 [here is the Java version of the viewer](https://bintray.com/tigervnc/stable/download_file?file_path=VncViewer-1.11.0.jar).
-If you are on OS11 (big Sur) [try this direct download](http://tigervnc.bphinz.com/nightly/osx/TigerVNC-1.11.80.dmg)
-If you are on OS10 (catalina) [try this direct download](https://bintray.com/tigervnc/beta/download_file?file_path=TigerVNC-1.10.90.dmg)
+If you are on Big Sur [try this direct download](http://tigervnc.bphinz.com/nightly/osx/TigerVNC-1.11.80.dmg). 
+If you are on Catalina [try this direct download](https://bintray.com/tigervnc/beta/download_file?file_path=TigerVNC-1.10.90.dmg).
+If you are on El Capitan [try this direct download](https://bintray.com/tigervnc/stable/download_file?file_path=TigerVNC-1.8.0.dmg)
+
 
 
 **Before** connecting, you need: