update readme for 5.6 beta 1 info

README.md

 # Unity Scriptable Render Loop testbed
 
-**NOTE**: this is a testbed for a Unity feature that has not shipped yet! The project will not work with any public
+**NOTE**: this is a testbed for a Unity feature that has not shipped yet! The project does not work with any public
 Unity version, and things in it might and will be broken.
 
 "Scriptable Render Loops" is a potential future Unity feature, think "Command Buffers, take two". We plan to ship the feature, and a
 There's a more detailed overview document here: [ScriptableRenderLoop google doc](https://docs.google.com/document/d/1e2jkr_-v5iaZRuHdnMrSv978LuJKYZhsIYnrDkNAuvQ/edit?usp=sharing)
 
 Did we mention it's a very WIP, no promises, may or might not ship feature, anything and everything in it can change? It totally is.
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+
+### For Unity 5.6 beta users
+
+* Unity 5.6 beta 1 should use an older revision of this project, [tagged unity-5.6.0b1](../../releases/tag/unity-5.6.0b1) (commit `acc230b` on 2016 Nov 23). "BasicRenderLoopScene" scene is the basic example, with the scriptable render loop defaulting to off; enable it by enabling the component on the camera.