How to Manually build plugin for android and IOS platform ?

I have one plugin with source code which works on android and IOS in Unreal Engine 4.14 , now I update the Unreal engine to 4.15, but the plugin does not work for 4.15.
How can I build the plugin Manually that can work on Unreal Engine 4.15 in both Android and IOS platform ?

Try the following (the runuat batch/shell script is in UE_4.15/Engine/Build/BatchFiles):

runuat BuildPlugin -plugin="<path/to/yourplugin.uplugin>" -targetplatforms=Android+IOS -package="<output path>" -rocket

Then copy the output into your Engine/Plugins folder, or have it output there directly.

Note that for iOS build you need to be on a Mac.