Thanks for the check Bryce, that confirms what I've found in my quick look before.

At least from the archives POV only libsoup2.4-tests needs it.
And as you outlined it added "Add patch to treat tests based on php-xmlrpc as unreliable" in 2.74.2-3.
And libsoup2.4-test are only in universe.

OTOH I would not want to drop it from the archive as you suggested. There might be 3rd party or user software using it, and it might be happy to use it for a long time.

Note: there also is php-xml-rpc2, but that seems less maintained - no need brought it back from [1].

So IMHO we could go either way from here:
a) keep it in main (process this MIR bug here)
b) or demote it to universe (update seeds)

Note: as it is only a wrapper around src:xmlrpc-epi that would go with php-xmlrpc either way 8as it is the only dependency).

As always this is a balance of importance/need vs maintainability.

Checking various resources it seems not only is [2] called unmaintained, but also the overall project [3] moved to a node.js based source in 2019.
xmlrpc-epi which it wraps seems to be static as well (not necesarily bad) with no real update since at least 2014 [4].

If you search the web for "php xml rpc" you'll find a lot, but no references to this library.
Instead most refer to it being a security mess for wordpress [5]. And it turns out that this #1 user of the concept makes no use of the extension that it php-xmlrpc. If it would make it faster or more secure you'd think that over the years it would have been used, but it is not.
And there is a disturbing amount of "other php xml rpc2 projects [10][11]... Does that mean this addon of PHP isn't any good/useful?

Considering what feature it provides (HTTP based RPC) you have some contenders [6] that are more common and supported. While Oauth is something else the other three serve a similar purpose. Yar isn't even packaged, xmlrpc is for debate here and SOAP clearly is the most known and used of them. SOAP is in main (e.g. php8.1-soap in jammy). Checking various articles about the topic always rate SOAP>XMLRPC [7][8][9].

The [12] the discussion/statement around the decision by the php project to split it from src:php 
could help as well. I consider their insight better than mine and they call it 'This extension was relatively unused, and was marked "experimental" all along. This extension relied on some of the libraries that were not maintained for several years.'
[12] Also lists four more modern alternatives for XML-RPC itself (none in the archive, no ITP for it in Debian).

It seems XMLRPC has lost the fight and on the way out. My gut feeling suggests to demote php-xmlrpc in Ubuntu 22.04 as a trial. If a reasonable real case comes up with use-cases needing support on php-xmlrpc we can re-promote it to main in 22.04. But as it seems to be on the way out I'd think for 22.10 and later we keep it in universe unless the conditions change on a wider scale.


@Bryce:
- Do you know of any other good way to check popularity/importance of php-xmlrpc to further guide our decision?
- If you agree would you prep the seed change?


[1]: https://tracker.debian.org/news/900929/php-xml-rpc2-removed-from-testing/
[2]: https://pecl.php.net/package/xmlrpc
[3]: http://xmlrpc.com/
[4]: http://xmlrpc-epi.sourceforge.net/
[5]: https://www.hostinger.com/tutorials/xmlrpc-wordpress
[6]: https://www.php.net/manual/en/refs.webservice.php
[7]: https://stackoverflow.com/questions/80112/whats-the-difference-between-xml-rpc-and-soap
[8]: https://maxivak.com/rest-vs-xml-rpc-vs-soap/
[9]: https://oriolrius.cat/article_fitxers/1842/xml-rpc_vs_soap.htm
[10]: https://tldp.org/HOWTO/XML-RPC-HOWTO/xmlrpc-howto-php.html
[11]: https://github.com/gggeek/phpxmlrpc
[12]: https://php.watch/versions/8.0/xmlrpc