How to integrate HTML5 platform extension to version 4.27?

Hi,
I am trying to integrate the HTML5 extension to the engine version 4.27. I have followed the documentation about 4.24 branch but that does no good for me, because I can’t open my project’s maps in that engine version. After that I tried to update the 4.24 to 4.27 from github but I couldn’t build the engine after that for some reason that I don’t know.
So, I have downloaded the HTML5 extension and tried to copy those files to my 4.27 engine source and I couldn’t build that too.
If someone knows how I can use the HTML5 platform extension in version 4.27, please point me to a right direction.
Thanks for your time.