diff --git a/INSTALL b/INSTALL
index 3ffd3a852..aa531099d 100644
--- a/INSTALL
+++ b/INSTALL
@@ -23,7 +23,7 @@ REQUIREMENTS
    - Net_IDNA2 0.1.1 or newer
    - Auth_SASL 1.0.6 or newer
    - Net_Sieve 1.3.2 or newer (for managesieve plugin)
-   - Crypt_GPG 1.4.3 or newer (for enigma plugin)
+   - Crypt_GPG 1.6.0 or newer (for enigma plugin)
 * php.ini options (see .htaccess file):
    - error_reporting E_ALL & ~E_NOTICE & ~E_STRICT
    - memory_limit > 16MB (increase as suitable to support large attachments)