Welcome to the Pulse: This week, we’re looking at how to use a 503 during brief PHP patch downtime, what robots.txt controls for AI crawlers and agents, and how Google handles bracket URLs and JPEG XL images.

Here’s what matters for you and your work.

Google Says Serve A 503 When Taking Sites Down For PHP Patches

In a LinkedIn post on Oct. 21, Google Search Central reminded anyone taking servers offline for PHP patches to return a 503 status code. The post went up the day PHP released emergency fixes for two critical flaws .

Key facts:

The post stated the 503 “ensures already indexed URLs are preserved in Search while you work” and noted to avoid general 404 or 200 error pages, and John Mueller of Google also shared a reminder on Bluesky saying that the 503 does not have to be served through PHP.…