diff --git a/lib/crypt.php b/lib/crypt.php
index 11ff095722..4a103f5285 100644
--- a/lib/crypt.php
+++ b/lib/crypt.php
@@ -179,7 +179,7 @@ public static function hash_compare($a, $b) {
         if (!is_string($a) || !is_string($b) || strlen($a) !== strlen($b)) {
             return false;
         }
-        /* requires PHP >= 5.6 */
+        /* requires PHP >= 7.4 */
         if (Hm_Functions::function_exists('hash_equals')) {
             return hash_equals($a, $b);
         }
diff --git a/lib/ini_set.php b/lib/ini_set.php
index e51c12bbfd..db4726c2b5 100644
--- a/lib/ini_set.php
+++ b/lib/ini_set.php
@@ -42,7 +42,7 @@
 ini_set('session.cache_limiter', 'nocache');
 
 /* session hash mechanism */
-if (version_compare(PHP_VERSION, 5.6, '==')) {
+if (version_compare(PHP_VERSION, 7.4, '==')) {
     ini_set('session.hash_function', 1);
 }
 else {
diff --git a/tests/phpunit/dispatch.php b/tests/phpunit/dispatch.php
index 14ace40a77..a12ca46a40 100644
--- a/tests/phpunit/dispatch.php
+++ b/tests/phpunit/dispatch.php
@@ -16,7 +16,7 @@ public function setUp(): void {
      * @runInSeparateProcess
      */
     public function test_is_php_setup() {
-        if ((float) substr(phpversion(), 0, 3) >= 5.6) {
+        if ((float) substr(phpversion(), 0, 3) >= 7.4) {
             $this->assertTrue(Hm_Dispatch::is_php_setup());
         }
         Hm_Functions::$exists = false;
diff --git a/tests/phpunit/mocks.php b/tests/phpunit/mocks.php
index 908fcc3abe..7dd663fa8a 100644
--- a/tests/phpunit/mocks.php
+++ b/tests/phpunit/mocks.php
@@ -264,7 +264,7 @@ public static function c_setopt() { return true; }
     public static function c_status() { return 200; }
     public static function c_exec() { return self::$exec_res; }
     public static function function_exists($func) {
-        if ((float) substr(phpversion(), 0, 3) < 5.6) {
+        if ((float) substr(phpversion(), 0, 3) < 7.4) {
             return false;
         }
         return self::$exists;