There is a lot of ambiguity in this thread. Yes, breaking changes need to be staged carefully/compatibly across versions. Simple renaming/reordering is not a

There is a lot of ambiguity in this thread. Yes, breaking changes need to be staged carefully/compatibly across versions. Simple renaming/reordering is not a breaking change between code versions. The wire format knows numeric ids, not names. It breaks code compilation until the renames are put into effect. There is a subtle breakage where someone renames a field (think: field -> old_field) and then later adds "field" to mean something else; software that isn't recompiled in this window might not recognize that "field" is potentially different. Uncompiled languages may suffer this even more subtly. -- All of this to say, breaking compilation is not the end of the world but there are more dragons as the scope grows. Stop-the-world is usually only needed when someone has made an unplanned/incompatible change with versions that are still running. If your infrastructure+development is done right (hah) this should never happen.