How to convert the array elements to lowercase using logstash

Elastic Stack Logstash
1

I have an array field in my elasticsearch document.

Array = ["German", "Spanish" , "English"]

I want to convert it to below format

Array = ["greman", "spanish", "english" ]

How can I convert the array content to lowercase while reindexing using Logstash?

Thanks in advance

2 
mutate { lowercase => [ "Array" ] }

results in

     "Array" => [
    [0] "german",
    [1] "spanish",
    [2] "english"
],