diff --git a/ext/random/random.c b/ext/random/random.c
index afd4cc1a77bb6..28411e4e1a1ef 100644
--- a/ext/random/random.c
+++ b/ext/random/random.c
@@ -480,11 +480,13 @@ PHP_FUNCTION(mt_srand)
 		Z_PARAM_LONG(mode)
 	ZEND_PARSE_PARAMETERS_END();
 
-	state->mode = mode;
-
-	/* Anything that is not MT_RAND_MT19937 was interpreted as MT_RAND_PHP. */
-	if (state->mode != MT_RAND_MT19937) {
+	switch (mode) {
+	case MT_RAND_PHP:
+		state->mode = MT_RAND_PHP;
 		zend_error(E_DEPRECATED, "The MT_RAND_PHP variant of Mt19937 is deprecated");
+		break;
+	default:
+		state->mode = MT_RAND_MT19937;
 	}
 
 	if (seed_is_null) {
diff --git a/ext/random/tests/01_functions/mt_srand_unknown_mode.phpt b/ext/random/tests/01_functions/mt_srand_unknown_mode.phpt
new file mode 100644
index 0000000000000..dc6129aaf10fa
--- /dev/null
+++ b/ext/random/tests/01_functions/mt_srand_unknown_mode.phpt
@@ -0,0 +1,24 @@
+--TEST--
+mt_srand(): Test unknown modes
+--FILE--
+<?php
+// MT_RAND_MT19937
+mt_srand(1, 0);
+var_dump(mt_rand());
+// MT_RAND_PHP
+mt_srand(1, 1);
+var_dump(mt_rand());
+// Unknown
+mt_srand(1, 2);
+var_dump(mt_rand());
+// Equivalent to 0 when cast as unsigned 8-bit integer
+mt_srand(1, 256);
+var_dump(mt_rand());
+?>
+--EXPECTF--
+int(895547922)
+
+Deprecated: The MT_RAND_PHP variant of Mt19937 is deprecated in %s on line %d
+int(1244335972)
+int(895547922)
+int(895547922)