New language JSON file not working

[Julia]

Hello

I've been trying to rewrite the JSON language files to work with an Icelandic keyboard. The JSON file I have been using is called is.json. However, when I try to set the language file, using 

DUCKY_LANG=is

it doesn't seem to change anything, as there is no difference between using 'is' and using 'us'. However, if I try to use one of the other available JSON files, for example dk.json, it works (I know because I am using a test payload that writes all allowed characters, there is no difference between 'is' and 'us', but 'us' and 'dk' differs).  
The is.json file currently resides in D:/languages when viewing the contents in arming mode. Currently, the Bash Bunny is running Firmware v1.5. 

Are there any additional changes I have to make in order for the is.json file to work properly? 

Thanks in advance!

Ps. This is the beginning of the test file: 

ATTACKMODE HID


LED R 

DUCKY_LANG=is
Q DELAY 1000

LED G  

msg_header="beginning"

RUN WIN notepad.exe 

LED B 

Q DELAY 200
Q STRING $msg_header
Q ENTER
Q DELAY 200

LED Y 

Q STRING "abcd 1234567890!\"#$%&/()=_{[]}\\-"
Q ENTER
Q DELAY 200 

After this part, there are just more strings and LED commands for debugging purposes. 

[MikeK]

I had a similar issue, this worked on mine:

• move .json to /languages folder
• add DUCKY_LANG xy to /config.txt (in your case: DUCKY_LANG is)
• don't use DUCKY_LANG in payload file(s)