At Laracon 2013 in Washington D.C., Taylor announced the first official release cycle for the framework.
The way releases are setup is that a new version of Laravel is released every six months, one around June and another at the end of each year. Bug fixes are provided for six months and security fixes for one year.
By having an official release cycle, it allows us as end users to plan around when we need to perform upgrades and also the dev team a way of knowing what is coming and when. Since this announcement all new releases have followed this schedule.
With the release of Laravel 5.1, a new cycle was added to offer long term support. It includes bug fixes for two years and security fixes for three.
This means 5.1 will be the only LTS version available until the two-year mark ends, June 2017. At that point, another LTS version will be announced. Here is an outline for the release schedule:
Proposed Release Schedule
Laravel 5.2
General release of 5.2 which includes 6 months of bug fixes, 1 year of security.
Laravel 5.3
6 months of bug fixes, 1 year of security.
Laravel 5.4
6 months of bug fixes, 1 year of security.
Laravel 5.5
The next LTS release. At this point Laravel 5.1 will no longer receive bug fixes, but will continue getting security fixes until June 2018.
Please keep in mind this is just a general guide and versions can change. My hope is this clarifies any confusion around how the release schedule is setup.