Bullet 2.89 (https://github.com/bulletphysics/bullet3/releases/tag/2.89) includes a new implementation of volumetric deformable objects and cloth based on the Finite Element Method, thanks to Xuchen Han. Two-way coupling between deformables and rigid/multi body is achieved using a unified constraint solver.
PyBullet is improved for robotics sim-to-real with realistic models of Laikago quadruped and an implementation of Deep Mimic (https://github.com/bulletphysics/bullet3/tree/master/examples/pybullet/gym/pybullet_envs/deep_mimic).