Unexpected a4a removal - myTarget implementation ("no cloudflare" solution)

[vfedoseev]

What's the issue?

myTarget implementation was removed with no notification.
Now we have faced the error in dev console:
Unknown attribute for mytarget: useA4a

We've encountered that our a4a extension was removed due to #26912
It seems that it caused by Cloudflare deprecation. However, our a4a implementation had nothing with Cloudflare and was used only for Fast Fetch and render non-signed creatives in 'nameframe'. All requests were sent only to our ad server.
Here is the last version: https://github.com/ampproject/amphtml/blob/e705eeac671b91871cc4efec408a7adc5324ea8c/extensions/amp-ad-network-mytarget-impl/0.1/amp-ad-network-mytarget-impl.js

Is there any way to revert it back?

How do we reproduce the issue?

Use myTarget Ad Implemetation:

<amp-ad width="300" height="250"
      type="mytarget"
      data-use-a4a="true"
      data-ad-slot="197378">
  </amp-ad>

What browsers are affected?

All browsers

Which AMP version is affected?

[vfedoseev]

Could anybody comment on the issue?

[lannka]

Unfortunately, fast-fetch is currently only available to ad servers who have the capability to serve AMPHTML ads. With the exit of CloudFlare supporting AMPHTML ads, all the ad networks by default will revert back to the delayed-fetch implementation. Let us know if delayed fetch is not working.

One good news is that we're actively working on "removing the AMPHTML ads signing requirement" after which we could make fast-fetch available to all ad networks. Stay tuned. See #27189

[vfedoseev]

Hello, @lannka!
Thank you for the detailed answer. Delayed fetch works now as a fallback, so we could fetch and render ad.