Howdy howdy. Here's what I'm thinking for the next release of 3.5. This week I'm going to merge / reject all the outstanding PRs for 3.5, then cut rc1 at the Python Core Dev sprints next week, either Monday (2019/9/9) or Tuesday (2019/9/10). This isn't a lot of notice, but things have slowed down a lot for 3.5, so I suspect nobody's going to be inconvenienced or bothered by the short notice.
However! If you would be inconvenienced or bothered by the short notice--if you need more time to get a patch in for 3.5--just let me know and I can delay rc1.
Assuming no problems crop up in rc1, 3.5.8 final will be released two weeks after 3.5.8 rc1.