From now on when a new Magento 1 Hypernode is created the default PHP version will be 5.6 instead of 5.5. Magento 2 Hypernodes will still be created with PHP 7.0 as the default setting. PHP 5.6 is a lot faster than PHP 5.5, check out this benchmark of an unoptimized Magento 1 shop with sample data on the same exact type of Hypernode with the only difference being the PHP version. Magento 1 Community Edition has been out of the box compatible with PHP 5.6 since You can still downgrade your new Hypernode to PHP 5.5 from the Byte Service Panel. If you want to upgrade your existing node to PHP 5.6 (or to 7.0, which is even faster), check out this article or this article.