diff --git a/core/version_api.php b/core/version_api.php
index 14b521d..036fa18 100644
--- a/core/version_api.php
+++ b/core/version_api.php
@@ -111,13 +111,14 @@ class VersionData {
 					if( $p_value == '' ) {
 						$t_value = date_get_null();
 					} else {
-						$t_value = strtotime( $p_value );
-						if( $t_value === false ) {
+						$t_date = date_create_from_format( config_get( 'normal_date_format' ), $p_value );
+						if( $t_date === false ) {
 							throw new ClientException(
 								"Invalid date format '$p_value'",
 								ERROR_INVALID_DATE_FORMAT,
 								array( $p_value ) );
 						}
+						$t_value = $t_date->getTimestamp();
 					}
 				}
 		}