The NSF-funded systems research testbed, Chameleon, has just been extended for another 4 years! Since public release 5 years ago, it has served almost 5,000 users working on research and education projects. Chameleon supports bare metal reconfiguration, custom kernel boot, and serial console access. Chameleon hardware combines scale with diversity, providing access to many different types of GPUs, interesting memory/NVMe/SDD configurations and SDN capable switches. To better support experimentation, Chameleon has been integrated with Jupyter and Zenodo, allowing users to easily create and publish experimental artifacts used in publications. In the new phase, Chameleon will provide support for IoT/cloud experimentation, even better support for networking experiments, and more support for reproducibility and experiment sharing.