FCMP++ features:

• Massive anonymity set increase — sender anonymity set goes from ~16 to over 160 million per transaction input (a 10-million-fold increase), giving Zcash-level sender privacy
• Carrot addressing protocol and new addresses — new address scheme with new view keys (also fixes issues like the burning bug and Janus attack, and enables outgoing view keys and offline address generation)
• Transaction relay v2 — bandwidth-efficient transaction relay (32-byte tx IDs instead of full ~10 KB transactions)
• RandomX v2 — improved ASIC resistance
• Proof-of-work commitments — better DoS/spam resistance for nodes; easier SPV-style wallet verification since proof-of-work can be checked without running a full RandomX hash (important for resource-constrained devices)
• Vastly improved multisig — no need for all parties to be online (or recently online) to sync key images; far fewer interaction rounds between participants
• Simplified hot/cold wallets and hardware wallet support — cold signing and vaults become much easier (part of why projects like XMR Bazaar and hardware wallet integrations struggled before)
• Signing before proving (decoupled signatures/proofs) — transactions can be signed ahead of time and membership proofs attached later, with no on-chain fingerprint distinguishing old vs. new signatures
• Transaction chaining / conditional spends — enables simple payment channel-style constructions (lock-time conditions, atomic-swap-style escapes) — an open PR by Teodor adds a basic version
• Faster wallet scanning — via the mx25519 library (~40% faster scanning compute in the assembly backends)
• Fungibility/privacy parity — closes the "Zcash is more private" sender-side gap; amounts and receivers were already protected

several of these (multisig relief, hot/cold simplicity, sign-then-prove) are the exact features Serai DEX is waiting on before launching its Monero integration.