SPA .. how can the client understand that the build of the new version is on the server?

Question

Frontend

The application is intensively sawn, every day a fresh build is assembled on the server. In the meantime, work is underway in it for its intended purpose, and people who use it practically do not cut down the computer and do not restart the browser, they don’t care .. problems naturally arise, and none of them knows what Ctrl + R is.
What are some good practices for dealing with this problem?
Here on vuejs.org, it seems, a button pops up in the lower right corner that there is a build update, how is it implemented? Really with each request through httpxmlrequest to drag build versions back and forth for verification and chop off caching in nginx, maybe there is some elegant solution? thank.
ps. backend - simple php, express_a is dumb