diff --git a/php.ini-dist b/php.ini-dist
index 426d4c30a10..e8d4a1e8a68 100644
--- a/php.ini-dist
+++ b/php.ini-dist
@@ -1143,6 +1143,9 @@ pfpro.defaulttimeout = 30
 ; 4: Overload ereg*() functions
 ;mbstring.func_overload = 0
 
+; enable strict encoding detection.
+;mbstring.strict_encoding = Off
+
 [FrontBase]
 ;fbsql.allow_persistent = On
 ;fbsql.autocommit = On
diff --git a/php.ini-recommended b/php.ini-recommended
index 7cab898a9a0..c0e8d3f5bde 100644
--- a/php.ini-recommended
+++ b/php.ini-recommended
@@ -1200,6 +1200,9 @@ pfpro.defaulttimeout = 30
 ; 4: Overload ereg*() functions
 ;mbstring.func_overload = 0
 
+; enable strict encoding detection.
+;mbstring.strict_encoding = Off
+
 [FrontBase]
 ;fbsql.allow_persistent = On
 ;fbsql.autocommit = On