Or must I delete the channel and upload again, losing all builds?
@Amos, is there any progress on this issue? I'm not speaking on previous version builds in a channel. It looks like it makes every previous build available for a channel's version available for installation, at least from the Itch.io desktop app. I can't think of a use case where someone would want to have them available, as they, at least in my case, are mistake builds (eg "oops, forgot to add a text file", etc.).
Does any non itch.io developer actually want to see previously uploaded builds for a version?
Yank logistical problems aside, perhaps just only show the most recent build under each version.