diff --git a/README.md b/README.md
index b4eec4269e..2f834caf51 100644
--- a/README.md
+++ b/README.md
@@ -21,6 +21,8 @@ npm install @aspnet/signalr
 
 **NOTE:** Previous previews of the SignalR client library for JavaScript were named `@aspnet/signalr-client`. This has been deprecated as of Preview 1.
 
+**IMPORTANT:** When using preview builds, you should always ensure you are using the same version of both the JavaScript client and the Server. The version numbers should align as they are produced in the same build process.
+
 The CI build publishes the latest dev version of the JavaScript client to our dev npm registry as @aspnet/signalr. You can install the module as follows:
 
 - Create an .npmrc file with the following line: