Version 9.0 already? To me this unfortunately signals lack of focus and/or disregard for backward compatibility, which means unnecessary churn for me as user of this project. Hard pass.
rqlite has been in development for 10 years[1], it's a long-running project and its design goals have never changed. The API hasn't changed in a breaking fashion since 2016 and rqlite has supported seamless upgrades for years now.
In other words rqlite users have been upgrading from version to version for over 8 years, without having to change a single line of their code.
Also rqlite doesn't support seamless downgrades between major versions, only seamless upgrades. I want to communicate that too (I've put a lot of work into the backup-and-restore system[1] so users can protect themselves if they are concerned about the seamless upgrade failing on them).
So by bumping the major version it helps people understand that they are upgrading to a substantially different version of rqlite, even if their client code doesn't have to change at all.