By XMRWallet Team · Published · 5 min read
2026 Note: The Fluorine Fermi upgrade activated successfully on July 16, 2022 at block height 2,688,888. All four changes described below are now live on the Monero network and affect every transaction. Ring size = 16, Bulletproofs+ active, view tags active. No user action is required.
Monero's network upgrade model — what cryptocurrency communities call a "hard fork" — is one of the project's most important governance mechanisms. Unlike contentious hard forks that split a blockchain into two competing chains (as happened with Bitcoin and Bitcoin Cash in 2017), Monero's hard forks are planned, non-contentious upgrades. The community agrees on improvements in advance; when the upgrade block height is reached, the new rules activate for all participants who have updated their software. No competing chain is created.
The July 2022 upgrade, named Fluorine Fermi, was one of the most significant Monero network upgrades in several years. It introduced four distinct improvements: a larger ring size, Bulletproofs+, view tags, and updated fee structure. Together these improvements strengthened Monero's privacy protections, reduced transaction overhead, and meaningfully improved wallet usability.
Change 1: Ring Size Increased from 11 to 16
Monero's ring signatures protect sender identity by combining the real spending output with a set of decoys drawn from the blockchain. The "ring size" is the total number of outputs in this set — one real, the rest decoys. Prior to the Fluorine Fermi upgrade, the mandatory minimum ring size was 11 (10 decoys + 1 real). The upgrade raised this to 16 (15 decoys + 1 real).
A larger ring size means a larger anonymity set — the group of plausible senders for any given transaction. With 16 possible senders instead of 12, blockchain analysis becomes significantly harder for any observer attempting to probabilistically identify the real spending output. This is one of the most direct protocol-level privacy improvements available to Monero. As of January 2026, ring size 16 remains the standard for all Monero transactions.
Change 2: Bulletproofs Upgraded to Bulletproofs+
Monero uses RingCT (Ring Confidential Transactions) to conceal transaction amounts. RingCT relies on range proofs — cryptographic proofs that a transaction output falls within a valid range without revealing the actual value. Bulletproofs (introduced in the October 2018 upgrade) dramatically reduced the size of these proofs compared to the original range proof system.
Bulletproofs+ is a further optimization that reduces proof size and verification time by an additional 5–7% compared to Bulletproofs. The practical effects are smaller transaction sizes (lower data overhead on the blockchain) and faster verification — benefiting both network nodes and wallet synchronization speed. Technical details are available from the Monero Research Lab.
Change 3: View Tags — 40% Faster Wallet Synchronization
Before the Fluorine Fermi upgrade, a Monero wallet scanning the blockchain to find incoming transactions had to perform a full cryptographic check on every transaction output to determine whether it belonged to the wallet. With millions of transactions in the blockchain, this scanning process was time-consuming.
View tags solve this by adding a single byte to each transaction output. This byte is derived from the shared secret between sender and recipient in a way that allows the wallet to instantly check whether an output might belong to it before doing the expensive full check. If the view tag doesn't match, the output is skipped entirely. This optimization reduces the total number of expensive cryptographic operations during blockchain scanning by approximately 40%, making wallet synchronization significantly faster — particularly noticeable after a wallet has been offline for an extended period. The improvement required no additional fees.
Change 4: Fee Structure Update
The upgrade also modified Monero's fee calculation parameters. The updated fee structure better reflects actual computational costs of transaction processing and improves the economic incentives for miners while keeping transaction costs low for users. Monero's dynamic block size mechanism allows fee adjustments without requiring additional hard forks for routine calibration.
Why These Upgrades Matter Beyond Technical Details
The Fluorine Fermi upgrade illustrates something fundamental about Monero's development approach: privacy and performance improvements are implemented at the protocol level, affecting every transaction by default — not as opt-in features. Every XMR transaction made since July 16, 2022 has a ring size of 16, uses Bulletproofs+, and includes a view tag. No user needs to configure or enable these protections.
The upgrade also laid technical groundwork for future development, including the ongoing Seraphis/Jamtis protocol work — Monero's next-generation transaction and address system currently in research and development as of 2026. Full technical documentation is available on the Monero Research Lab page and the Monero GitHub repository.
For XMRWallet users, all Fluorine Fermi improvements applied automatically — no user action was required then or now. XMRWallet remains fully compatible with the current Monero protocol.
Frequently Asked Questions
What was the Monero Fluorine Fermi upgrade?
Fluorine Fermi was Monero's July 16, 2022 hard fork (block height 2,688,888). It raised ring size from 11 to 16, upgraded Bulletproofs to Bulletproofs+, introduced view tags for ~40% faster wallet sync, and updated the fee structure. All changes are now live on the Monero network.
Why did Monero increase the ring size from 11 to 16?
A larger ring size means a larger anonymity set — more plausible senders for any given transaction, making blockchain analysis harder. Ring size 16 means each spend has 15 decoys plus 1 real output. Increasing from 11 to 16 directly strengthens sender privacy at the protocol level.
What are view tags in Monero and why do they help?
View tags are a single byte added to each transaction output that allows wallet software to quickly skip outputs that don't belong to the wallet without performing a full cryptographic check. This reduces the number of expensive operations during blockchain scanning by ~40%, significantly speeding up wallet synchronization with no additional fee.
