diff --git a/INSTALL.md b/INSTALL.md
index 5867196d..8d421ec1 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -12,7 +12,8 @@ the options and adjust them as you see fit.
 
 - PHP version 5.3 or above
 - _one_ of the following sources of cryptographically safe randomness is required:
-  - PHP 7
+  - PHP 7 or higher
+  - open_basedir access to /dev/urandom
   - [Libsodium](https://download.libsodium.org)
   - mcrypt extension
   - com_dotnet extension