Feature Launch · Brutalist

It opens: "KESTREL RELEASE / 3.0 ROLL BACKS IN 400ms A rollback used to mean a rebuild, a redeploy, and four minutes of staring at a progress bar while your on-call phone buzzed. Kestrel 3.0 keeps the last twenty builds warm. Reverting...". Preheader: "Rollbacks now take 400 milliseconds, not four minutes.". Links: "Read the release notes". 0 images, 3 Outlook-only blocks, no dark-mode query, system fonts.

The spread is what matters on this template: 100 in Superhuman against 91 in Outlook Classic, a 9-point gap across the same file. 18 of the 21 clients render it without a single flagged property. Outlook Classic is the one to preview against after any edit, because it is where this template has the least margin, and the 71 warnings behind that score are concentrated there rather than spread evenly.

At 7.2KB compiled it has roughly 95KB of headroom before Gmail clips the message at 102KB and hides the rest behind a "View entire message" link. Inlined CSS and base64 images both count toward that, so watch it as you add sections.

Safe to customise: The screenshots and the walkthrough copy. This is the longest thing most products send, which makes total size the constraint to watch rather than layout.

Leave alone: The heading hierarchy. It carries the outline screen readers announce, and flattening headings into styled text is the most common accessibility regression in announcement mail.

Modified it? Check your version against the same 21 clients.