Unless you're trying to fix some specific problem using 1.5.3 I suggest using 1.5.0 and waiting for 1.5.4: http://bbs.espressif.com/viewtopic.php?f=7&t=2104
@tve started
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
Unless you're trying to fix some specific problem using 1.5.3 I suggest using 1.5.0 and waiting for 1.5.4: http://bbs.espressif.com/viewtopic.php?f=7&t=2104