Blizzard will Soon(tm) introduce multiple TOC files, allowing the same .zip download to be used in all game editions.
MyAddon.toc (fallback if the others are not present)
The website appears to already support multiple-version support with a download marked 'alpha'. I havn't yet tested with flagging a download as 'beta' or 'release'; which will be necessary to test the curseforge client.
Does anyone know if CurseForge will be able to support this, as 2.5.1 and 9.1.0 release?