diff --git a/doc/htconfig.md b/doc/htconfig.md
index a7dd59d1f5..a2da0ed9c7 100644
--- a/doc/htconfig.md
+++ b/doc/htconfig.md
@@ -25,6 +25,7 @@ Example: To set the directory value please add this line to your .htconfig.php:
 * **allowed_link_protocols** (Array) - Allowed protocols in links URLs, add at your own risk. http is always allowed.
 * **birthday_input_format** - Default value is "ymd".
 * **block_local_dir** (Boolean) - Blocks the access to the directory of the local users.
+* **auth_cookie_lifetime** (Integer) - Number of days that should pass without any activity from a before before the users who choosed "Remember me" when logging in from that browser is considered logged out.
 * **curl_range_bytes** - Maximum number of bytes that should be fetched. Default is 0, which mean "no limit".
 * **db_log** - Name of a logfile to log slow database queries
 * **db_loglimit** - If a database call lasts longer than this value it is logged