Mycorrhiza has been through numerous releases. This hypha lists them in reverse chronological order (the most recent release is on the top).
You can download all releases on GitHub. Announcements about new releases are also made on u/bouncepaw's Telegram channel (in Russian).
You should always stick to the latest version. Security and stability fixes are never back ported.
Note that version 0.6 was never been released, and 0.5 is the first released version.