In module 2.4, we'll examine off-chain scaling solutions, including side-chains and rollups, including zk-rollups and optimistic rollups.
Further reading:
Blockchain Scalability - Sidechains and Payment Channels
A Beginner's Guide to Bitcoin's Lightning Network
Optimistic vs. Zero-Knowledge Rollups: What’s the Difference?
What Is Zero-knowledge Proof and How Does It Impact Blockchain?