The RN is now available on the Customer Portal:
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/8.3_release_notes/technology_previews#BZ-1889737

Update for RHEL 8.4:

For XDP, we're now supporting also the redirect and tx verdicts. Meaning the sentence "The XDP_TX and XDP_REDIRECT return codes." should be removed from the Technology Previews / Networking chapter.

The "XDP is conditionally supported" section in New Features / Networking sections should be adjusted. I propose the following wording: 

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With this release, the XDP_TX and XDP_REDIRECT return codes are now supported in XDP programs.

Red Hat supports the eXpress Data Path (XDP) feature only if all of the following conditions apply:

* You load the XDP program on an AMD or Intel 64-bit architecture
* You use the libxdp library to load the program into the kernel
* The XDP program does not use the XDP hardware offloading 

For details about unsupported XDP features, see Overview of XDP features that are available as Technology Preview.
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Longer term, we'll need to find a better place for the support conditions. The libxdp condition is going to stay for the RHEL 8 lifetime and having this in the New Features forever does not look correct.

For some reason, the 8.3 release notes contain two sections in the Technology Previews / Networking chapter: "XDP available as a Technology Preview" and "XDP features that are available as Technology Preview". These should be merged.

> For some reason, the 8.3 release notes contain two sections in the Technology Previews / Networking chapter: "XDP available as a Technology Preview" and "XDP features
> that are available as Technology Preview". These should be merged.

I merged the RN from this BZ and BZ#1503672.
The merged RN is now here in this BZ (see DocText field)


To track the "what-is-supported-in-8.4" part of XDP, I created BZ#1952421 for the corresponding RN.

The KI (BZ#1880268) was fixed in RHEL 8.4. I removed the reference to the KI from the RN.