Yeah this is correct - 2026.8.0-latest is a lower version than 2026.8.0. You can confirm with a Semver parser. e.g. in ruby:
irb(main):001> Gem::Version.new("2026.8.0-latest") < Gem::Version.new("2026.8.0")
=> true
We should fix that. Theme authors should be able to do:
minimumDiscourseVersion: "2026.8.0-latest"
Although as @moin mentinoed, that can be risky since -latest refers to a whole ton of different commits. So in a perfect world, we should wait until the next release before depending on a new core feature from a theme/plugin.