runtime not allowed when migrating from java7 to java8

[Angel Koh]

Hi, 

I'm following this migration guide https://cloud.google.com/appengine/docs/standard/java/migrating-to-java8 

and it says that i should add 

<runtime>java8</runtime> to your appengine-web.xml file and redeploy the app.

When i try to do it, I get "Element runtime is not allowed here" error. should i change any other things in the gradle build? 

I've also posted a question at https://stackoverflow.com/questions/48072989/gae-migration-from-java-7-to-8-on-android-studio

[Katayoon (Cloud Platform Support)]

I would like to continue with the thread you made on Stack Overflow since you will get more visibility on your question.