We just released Mastodon v4.7.2, v4.6.8, v4.5.18 and v4.4.25. In addition to several bugfixes, they disable HEIF processing to avoid a known critical security issues. We encourage server administrators to update as soon as possible. Full release notes and update instructions are available on the GitHub releases page. https://github.com/mastodon/mastodon/releases #MastoAdmin