Convergent Capabilities: A new capability model appropriate for CRDTs, and sits between object- and certificate-capabilities A Group Management CRDT: Self-certifying, concurrent group management complete with coordination-free revocation E2EE with Causal Keys: With post-compromise security (PCS) and symmetric key management granting access to causal predessesors. By following the links, it both lets a writer know who has read access (i.e. who to share keys for the latest E2EE chunk with), and lets the trust-minimized sync engine know which documents the current device can request from the server. Causal Encryption Causal key management: a strategy for managing E2EE keys based on the causal structure of a document.