add note on readline support

diff --git a/UPGRADING b/UPGRADING
index 8208adbae8cfd47c96dae52d133bd3fd2e93fa64..dc08ba3aadc0784b5978f6b399f8433e5ac6406d 100644 (file)
--- a/UPGRADING
+++ b/UPGRADING
@@ -110,6 +110,16 @@ PHP 7.1 UPGRADE NOTES
     the first php-fcgi.exe process will exec the specified number of children.
     Those will share the same TCP socket. 
 
+- readline:
+  . The readline extension is supported through the WinEditLine library
+    (http://mingweditline.sourceforge.net/). Thereby, the inteactive CLI
+    shell is supported as well (php.exe -a).
+
+    It is well known, but nevertheless is worth mentioning again, that
+    the readline extension is not thread safe and will never be. Thus,
+    the usage of it with any true thread safe SAPI (like Apache mod_winnt) is
+    strongely discouraged.
+
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 13. Other Changes
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