Multiplatform Framework with Bitcode

Hello, I noticed from the updated FAQ that you can enable bitcode for the Kotlin framework:

targets {
    fromPreset(presets.iosArm64, 'myapp') {
       compilations.main.outputKinds 'FRAMEWORK'
       compilations.main.extraOpts '-Xembed-bitcode' // for release binaries
       // or '-Xembed-bitcode-marker' for debug binaries

However when I try to generate the frameworks it gives me the warning:
warning: flag is not supported by this version of the compiler: -Xembed-bitcode and the framework does not contain bitcode.

My current kotlin plugin version is: 1.3.0-rc-190-Studio3.2-1. Please let know what I can do to generate bitcode with the framework. Thanks!