Core doesn't have %S anywhere in a string and the only installation language file that does is Italian.

With one exception which is the date format and I assume still works
DATE_FORMAT_CALENDAR_DATETIME="%Y-%m-%d %H:%M:%S"

Just checked and it is nothing to do with php 8.1

Capital S has always been wrong and has never worked.

The only difference since 8.0 is that since 8.0 it no longer returns false on failure.

In php <8.0 using %S would not error but it would not do anything

before to switch on php 8.1 i was able to install joomla 4 .0 and 4.1 after i cannot

Thats because it no longer returns false on error. It has always been wrong just that previously it was a silent error

In any case, that string has to be corrected ASAP for tomorrow's release. Patch by @alikon is correct. Reply by whoever is Joomla CMS is totally wrong.

BTw if anything this should be patched via crowdin -> synced to core-translations -> updated the CMS and not directly via a PR against this repo. Else this issue will come back on the next release.

This change have to be made in crowdin in and merged thru the translation-bot, if not if will be overwritten with the next sync (and breaks the bot).

@HLeithner please consider merging #36222 before the bot will run again. One of the error pages has no translations...

dears, i've already made the change 1st in crowdin but has been rejected, as I posted in the pr

I have contacted wilco to check what went wrong on the crowdin side so this can be sorted.

Just for the record this PR should not be directly merged as it is (yes I know the change is correct) but it has to go via crowdin, core-translations and the bot. ;)

for tomorrow's release.

Cancelled. Apparently. https://twitter.com/joomla/status/1467866831159545861

Yeah we've pushed it back by a week - because of the stuff I had to merge on Sunday already put the release team on short notice plus then I have this plus Dimitris' one he linked plus this - it's just safer to push it back by a week and get everything properly tested and time to settle

Fixed in #36226