Lighttpd 1.4.54 webdav 0b files & multiple stubby instances

Hi guys, I'm using Lighttpd as a web-dav service which its version is 1.4.54, when I create or upload files to it, those files are stored as 0 byte files, and my router is running OpenWRT 19.07.2.
From this link:
the bug was fixed in version 1.4.55, and I hope I can upgrade to the next version in the near future.

Another problem is: how to run multiple stubby instances which are run by stubby user?
I just know, in terminal, command

stubby -c /etc/stubby/stubby.yml -g

will work, but it's run by root user not stubby.

Sorry about my bad English, I'm still improving it.:pleading_face: