$this is a syntax error when using static classes (#5264)

core/software/resources/classes/software.php

@@ -19,7 +19,7 @@ if (!class_exists('software')) {
 		 * numeric_version
 		 */
 		public static function numeric_version() {
-			$v = explode('.', $this->version());
+			$v = explode('.', software::version());
 			$n = ($v[0] * 10000 + $v[1] * 100 + $v[2]);
 			return $n;
 		}