Would like to post a job advert somewhere in English, with good exposure to reach developers with at least 10 years of experience, preferably in a range of languages/projects.
(Can post in Chinese if necessarly, but I feel like starting out in English is helpful if majority of the comm is going to be in English.)
Ideas? 
Linkedin for “English” and 104 for “Chinese”.
And of course, share here too, you can do it in private if you would prefer, depending on what kind of developers you are looking for, I might help with indications.
Most of what they would be doing is one of these:
misc maintenance of legacy systems for customers, (mostly bash scripts, PostgreSQL, PHP, JS)
misc glue/utility code for one-off projects, (typically bash or PowerShell)
internal projects (mostly utility scripts in Ruby or bash to connect MS-SQL databases to external vendor APIs)
The first two being pretty small/random stuff and the latter being an on-going need.
The key attributes we’re looking for would be cross-platform (and/or cross-industry) experience. Anybody can code, and once you’ve been exposed to half a dozen languages it’s easy to pick up whatever’s new or forgotten, but for somebody to write good (maintainable!) code requires a broader range of experience and awareness of best practices, (documentation, zomg!)
Fortunately none of this is ever screamingly urgent, so no need to work on a different time-zone or anything. 