[php-src] master: [skip ci] Update UPGRADING.INTERNALS for #21607

Author: Weilin Du (LamentXU123)
Date: 2026-07-22T22:35:44+08:00

Commit: https://github.com/php/php-src/commit/83eea8793043c47c799193cefe92765a7281dea8
Raw diff: https://github.com/php/php-src/commit/83eea8793043c47c799193cefe92765a7281dea8.diff

[skip ci] Update UPGRADING.INTERNALS for #21607

Changed paths:
  M  UPGRADING.INTERNALS


Diff:

diff --git a/UPGRADING.INTERNALS b/UPGRADING.INTERNALS
index ef5155e39db6..666d7830a5f8 100644
--- a/UPGRADING.INTERNALS
+++ b/UPGRADING.INTERNALS
@@ -145,6 +145,9 @@ PHP 8.6 INTERNALS UPGRADE NOTES
     (sendfile, splice, copy_file_range, TransmitFile), and is now used by
     php_stream_copy_to_stream_ex(). The mmap-based copy fallback was removed.
   . Added zend_string_equals_cstr_ci().
+  . Added zend_cstr_append_char(), zend_cstr_concat(), and
+    zend_cstr_concat3() as helper functions to allocate NUL-terminated raw C
+    strings from one or more buffers.
   . Added zend_string_ends_with() and related variants.
   . Added trait support for internal classes.