Curious to know how many people do zero-downtime deployment of backend code and how many people regularly take their service down, even if very briefly, to roll out new code.
Zero-downtime deployment is valuable in some applications and a complete waste of effort in others, of course, but that doesn’t mean people do it when they should and skip it when it’s not useful.
On the flip side, if something goes wrong and your service is backwards compatible you can roll back without any more issues. If you allow downtime and backwards incompatible changes rollback can cause even more problems and result in far longer outages and lots of very stressed programmers.
You should always be able to roll back code changes. And zero downtime deployment are not that hard to do if you are already enforcing that.