Often nobody even sees them. The software gets built by a CI system, there's no way for the CI system to alert on new warnings appearing, and nobody checks the

Often nobody even sees them. The software gets built by a CI system, there's no way for the CI system to alert on new warnings appearing, and nobody checks the logs. Maybe a staged process. Start with a warning as usual, to CYA. Nobody will care, but you can feel smug and say you told them. Then turn it into an error and add a flag that a user can set to turn that deprecation back into a warning. Setting the flag should be a trivial change, but since builds will fail it'll be noticeable. The build failure message should include the date the deprecated feature will be removed, a link to migration steps, and instructions on how to set the flag to allow builds to succeed. Then finally remove the feature. That would allow users a chance to schedule work to remove use of the deprecated feature.