In Ubuntu, LTS stands for "Long Term Support". An LTS release is a version of Ubuntu that is maintained for an extended period, typically five years, with security updates and bug fixes. LTS releases are considered the "enterprise-grade" releases and are typically used for production servers that need security and reliability, like web hosts. In contrast, non-LTS releases are supported for only nine months and do not receive the long-term commitment of LTS releases. The LTS designation applies only to specific subsets of the Ubuntu archive, and the project decides which flavors will be LTS and the support duration for each early in the LTS development cycle. Upgrades to new versions of Ubuntu are always free of charge.