https://www.cnet.com/news/spacex-to-come-out-of-beta-with-its-block-5-falcon-9-rocket/

This week's scheduled launch of a Falcon 9 carrying Bangladesh's Bangabandhu Satellite-1 will be the debut of the so-called Block 5 Falcon 9. 

SpaceX refers to the iteratively improved versions of the Falcon 9 by their block number. Most of the recent Falcon 9 rockets that have managed to land and then fly a second mission after reconditioning have been Block 3 or Block 4 (sometimes called "Full Thrust") rockets. Elon Musk has said that Block 5 represents the final upgrades to the Falcon 9, incorporating tweaks to make it more reusable while adding a little more power and minor improvements that provide more control on descent.