Five rockets of the version 1.0 design were launched from June 2010 to March 2013. Version 1.1 had fifteen launches from September 2013 to January 2016. The "Full Thrust" version has been used since December 2015. There are many upgrades to this version. The latest Full Thrust variant, Block 5, was introduced in May 2018. It has more thrust, improved landing legs and other minor improvements to help recovery and reuse. The Falcon Heavy version was first flown in February 2018. It has a stronger Falcon 9 first stage as its center core. It also has two added Falcon 9 first stages used as boosters. SpaceX plans to replace Falcon 9 and Falcon Heavy with the much larger Starship launch system.