Update prerequisites.md

Author: ConnorLand

content/en/docs/refguide/mobile/getting-started-with-mobile/prerequisites.md

@@ -17,7 +17,9 @@ While developing Mendix apps, you will need to test and iterate to make the best
 * The [Troubleshooting Common Mobile Issues](#troubleshooting) section explains port forwarding, WiFi settings, and other common troubleshooting issues
 
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-Please note that instructions in this document reference Mendix 9 technologies. After the Make It Native 10 app is published in app stores, this document will be rewritten to describe testing Mx10 apps.
+Please note that instructions in this document reference Mendix 9 technologies. When using Mx10 Beta 1 or Beta 2, please use the Make it Native 9 app while testing.
+
+After the Make It Native 10 app is published in app stores, this document will be rewritten to describe testing Mx10 apps.
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 ## 2 Getting the Make It Native App {#get-min-app}