diff --git a/src/error/PhutilOpaqueEnvelopeKey.php b/src/error/PhutilOpaqueEnvelopeKey.php
--- a/src/error/PhutilOpaqueEnvelopeKey.php
+++ b/src/error/PhutilOpaqueEnvelopeKey.php
@@ -36,7 +36,7 @@
       // Phabricator on systems where we can't read it.
       self::$key = '';
       for ($ii = 0; $ii < 8; $ii++) {
-        self::$key .= md5(mt_rand(), $raw_output = true);
+        self::$key .= md5((string)mt_rand(), $raw_output = true);
       }
     }
     return self::$key;
diff --git a/src/filesystem/Filesystem.php b/src/filesystem/Filesystem.php
--- a/src/filesystem/Filesystem.php
+++ b/src/filesystem/Filesystem.php
@@ -788,7 +788,7 @@
 
     $tries = 3;
     do {
-      $dir = $base.substr(base_convert(md5(mt_rand()), 16, 36), 0, 16);
+      $dir = $base.substr(base_convert(md5((string)mt_rand()), 16, 36), 0, 16);
       try {
         self::createDirectory($dir, $umask);
         break;
diff --git a/src/future/http/HTTPSFuture.php b/src/future/http/HTTPSFuture.php
--- a/src/future/http/HTTPSFuture.php
+++ b/src/future/http/HTTPSFuture.php
@@ -817,7 +817,7 @@
 
     $osx_version = PhutilExecutionEnvironment::getOSXVersion();
     if ($osx_version) {
-      if (version_compare($osx_version, 14, '>=')) {
+      if (version_compare($osx_version, '14', '>=')) {
         return false;
       }
     }