The R15 memory limit has been lowered to 200%
Change effective on 04 April 2016
In order to improve our platform health and stability, the R15 - Memory quota vastly exceeded error has been lowered. Originally, this limit was triggered at 500% over the limit and it will now trigger at 200% over the dyno memory limit. For more information on this error, please review this Dev Center article.
In addition to this, the transitional error R151 has been removed.