Pull Request for Issue #41114 #35376 .

Summary of Changes

In older J! versions (1.6 - 3.10) an update server XML feed for an extension could define the client_id (Admin or Site) as a numeric value (0 or 1) OR as a string (admin or site).

The support for numeric values was removed in 4.x. If an update server still uses numeric IDs, this will cause a PHP notice being triggered as described in #41114 or #35376.

A PR re-allowing numeric IDs in J4 was opened (and closed) a while ago, see #35822

This PR essentially rebuilds the mentioned PR, however removed the deprecation notice.

Why removing the deprecation? Because I assume that the issue will update feeds using legacy IDs will remain relevant in the near future. Devs are unaware that their feed causes the notice, as it's invisible to end users in normal backend scenarios: after the update retrieval Joomla (which triggers the notice) the user is redirected to the update overview again - and because of the redirect, the actual notice isn't shown to end users or devs, even with debug error reporting. The issue is only visible in logs files or non-backend usecases like CLI (see #41114) or when the output of the request that includes the update retrieval is parsed (like we do in the backupmonkey.io client in order to get the current update list - here the notice breaks our JSON response, that's why the client currently includes a specific workaround because the issue is VERY widespread).

Testing Instructions

Reproduce issue, see #35376

Actual result BEFORE applying this Pull Request

Notice logged

Expected result AFTER applying this Pull Request

Notice gone