Drag upload pictures in 2.7.3

Hello,
Sorry i posted this question in pre-sales the first time, please delete it there.
I would like to implement the change you made in 2.7.4 "Drag upload pictures when modifying propety at front-end" in 2.7.3 .
I know what changes to make in propertyedit.php. See image.
Can you tell me which other files i have to modify?
Thank you!

Hi,
You need to uploaded 2 files: upload.php and upload.html.php in folder "classes" too
Thanks
Dam

Hello Dam,
I made the changes in propertyedit.php and uploaded the 2 files: upload.php and upload.html.php in folder 'classes'.
Now when i go to front-end edit property and click to drag upload pictures it takes me to this url:
index.php?option=com_osproperty&task=upload_ajaxupload&tmpl=component&id=38 and it's a blank page. Only the name of the site is shown at the top left corner, nothing else.
Is there any other change i need to do to make it work?
Thank you

Hi,
Sorry, i forgot to tell you to update file: components > com_osproperty > helpers > helper.php
Thanks
Dam

Hello Dam,
Sorry but i cant get it to work.
I also updated helper.php but i still have blank page when i press to upload with drag and drop fuction.

Sorry, you need to update file: components > com_osproperty > osproperty.php
There are some language constants you need to translate too
Thank
Dam