Bug #77555 [NEW]: Why does mb_strtoupper change 'ß' to 'ss' in words like 'groß'?

From: dirk dot gerigk at atraveo dot com Operating system: Windows 10 PHP version: 7.3.1 Package: *Unicode Issues Bug Type: Bug Bug description:Why does mb_strtoupper change 'ß' to 'ss' in words like 'groß'? Description: ------------ I try to understand why this was implemented. When you do print mb_strtolower("Groẞ"); it becomes 'groß' UPPER CASE ẞ becomes LOWER CASE ß print mb_strtolower("Groß"); will be 'groß' LOWER CASE ß unchanged print mb_strupper("groẞ"); will be 'GROẞ' UPPER CASE ẞ stays unchanged! But print mb_strtoupper("groß"); becomes 'GROSS' Why does it not become UPPER CASE ẞ? Not all words in german can be changed in that way and should only changed if needed. UPPER CASE ẞ is offical see https://en.wikipedia.org/wiki/Capital_%E1%BA%9E Test script: --------------- print mb_strtoupper("groß"); Expected result: ---------------- GROẞ Actual result: -------------- GROSS -- Edit bug report at https://bugs.php.net/bug.php?id=77555&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=77555&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=77555&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=77555&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=77555&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=77555&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=77555&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=77555&r=needscript Try newer version: https://bugs.php.net/fix.php?id=77555&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=77555&r=support Expected behavior: https://bugs.php.net/fix.php?id=77555&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=77555&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=77555&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=77555&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=77555&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=77555&r=dst IIS Stability: https://bugs.php.net/fix.php?id=77555&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=77555&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=77555&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=77555&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=77555&r=mysqlcfg