Nakamoto Progress Update: Code Complete On-Track & Primary Testnet is Back!
Hey Stackers, as core developers push hard toward Nakamoto Activation I wanted to bring you a few exciting updates about their recent progress. TL;DR: They are on track for reaching Code Complete on the new code needed for Activation and the Primary Testnet is back.

If you remember from our previous post, core developers are taking additional time on work related to Signer and Miner resiliency after having an opportunity to work with these stakeholders and see the system working in real time. As they continue working, here are some of the exciting bits to note:
Code complete progress
On-track. 63% of new issues are already completed, any additional time will be used toward extra testing of new code.

Primary Testnet operation is fully restored
As you may know, ongoing issues with the Bitcoin testnet were wreaking havoc on the Stacks testnet. Over the past few weeks, core developers have migrated the testnet to Bitcoin Regtest, a much more stable Bitcoin testnet. Long story short, the Primary testnet is back and ready for builders, partners, and others to work against!

Please jump to this section of the docs if you would like an overview of the testnets to help you decide which you’d like to use.

Improved multi-sig support (thanks to Vlad!)
This update will now ship with Nakamoto Activation; it greatly enhances the multi-sig experience on Stacks, paving the way for user-friendly and powerful multisig wallets. It streamlines the signing algorithm and removes the need for in-order signing without increasing the transaction size or compromising on security. Learn more in this thread.

Simplifying Signer signature aggregation (for now)
The original Nakamoto implementation details call for Signers to aggregate their signatures via WSTS. WSTS is a system for making Weighted Schnorr Threshold Signatures. It allows a group of signers, each of whom controls a set of keys, to make a valid Schnorr signature, as long as T (the threshold) of them complete the protocol honestly. WSTS is still very much the plan, but will now be implemented before the final version of sBTC instead, recognizing that it is not work that needs to be done before Activation. This further simplifies implementations for Signers during the upgrade, as the signer set will use a concatenation of signatures (like Bitcoin’s P2SH multisig). Core devs and Signers have drafted a ‘rider’ SIP to detail the adjustment which will go to the Technical CAB for review. Please join the upcoming SIP call if you have questions.

Work on timestamps is underway
DeFi builders will be happy to know that in parallel with other work, core developers have begun working to add timestamps to block headers. Among other benefits, native time-stamping would allow builders to streamline smart contracts and reduce critical dependencies on oracles. You can dive deeper on the Github issue here.

We'll post another update from the frontlines of Core Development in ~2 weeks, until then follow @stacks on Twitter or subscribe to Stacks Snacks!
Showcase: See Bitcoin builders in action
Don’t miss the next big community gathering: The Building on Bitcoin Virtual Showcase is June 13th. Hear from builders across the Stacks ecosystem discussing the work they are doing, information about their apps, and how you can use their products or get involved.