A Long Term Support Release is a version of Weave that will be supported for a longer than normal time. It is a release for customers who have a stable production system and do not need or want want to be updating their system all the time.
Our newest Long Term Support Release is 2.5.15. If there are any bug fixes then they are applied to the Last Stable Release and the Long Term Support Release. Please be aware that if there are enhancements, they are only applied to the Last Stable Release.