I’m confused: do people pay attention to version numbers or not? >
They pay attention when they go to upgrade. For example when reading NEWS.txt or CHANGES.txt it is a prerequisite you know what version you are on. Many users know, while many others don't because it's so easy to figure out on-the-fly. I don't want to stereotype the user base here. As you say we have flexibility with the definition of semver. Since we are an always-on technology we have the opportunity to define what a significant breaking change means to us. I believe we can and should use this opportunity to the benefit of our users, and from experience upgrades are an area where we can (and need to) make things simpler. We can do this by defining it as a) the removal of deprecated APIs, and b) dropping backward compatibility with the previous-previous major. If we want to maintain our backward and forward compatibility forever we should do away with major versions altogether. I'm not in favour of doing that. It creates significant overhead for both engineers and testing resources. And it also misses an incentive to push users to stay up to date.
