wroclove.rb 2019 lightning talk by a self-described Ruby back-end developer masquerading as a front-end person. Frames outdated-browser support as an economics problem: businesses with unlimited money can support every browser, but most can't, so the front end typically uses an NPM package that is kept up-to-date with a list of supported browsers/versions, combined with another package that validates the HTTP User-Agent against that list and shows an 'update your browser' message. This breaks when the browser doesn't support JavaScript (or it is disabled), so the problem falls to the back end — hence a Ruby port of the NPM package that does the same User-Agent matching and renders the alert in pure HTML. The remaining issue is keeping a single source of truth for the supported-browser config: in a usual Rails project where front-end and back-end share a repo, share the browsers JSON file; when the front end is a separate repo/service, issue an HTTP request from the back end to the front end per request (which can be cached) to get the config.