Bitcoin (BTC) is undergoing an upgrade to its protocol called Taproot, announced last week, after gaining enough mining support to lock in activation. By the time that the 2 difficulty periods end on Sunday, it is likely that Taproot will be locked in with over 99% of blocks signaling in favor. The most anticipated upgrade since Segregated Witness (SegWit) in 2017, Taproot will replace Bitcoin's elliptic curve digital signature algorithm with a new digital signature scheme known as Schnorr signatures.

The change to Bitcoin's code opens up options for privacy, multi-signature wallets, security, and scaling. The next activation phase is a 5-month waiting period, when miners and nodes update their software to Bitcoin Core 0.21.1, the newest version that contains activation logic for the Taproot soft fork and other updates. Finally, when Bitcoin reaches block 709,632, Taproot will automatically activate, meaning all upgraded nodes and devices will recognize and accept transactions created using Taproot. Then Bitcoin developers will be able to build more on Taproot's features in order to improve the user experience.

Here is the rest of the week in review:

Ledger announced Thursday it raised $380 million in a massive Series C funding round led by digital asset fund 10T Holdings. The Paris-based hardware wallet maker said the participating investors also included Cathay Innovation, Draper Associates, Digital Currency Group, Korelya Capital, and Wicklow Capital, among others. Ledger said the fundraise gave it a new implied valuation of over $1.5 billion, marking rapid and accelerating growth. Ledger previously raised a $7 million Series A in 2017 and a $75 million Series B in 2018. 10T Holdings founder Dan Tapiero added he will join Ledger's board: "We believe Ledger is the premier security company and premier brand name in the cryptocurrency/blockchain space." Legder said it will use the fresh capital to invest in innovation of its products and provide new decentralized finance services.

Invesco (IVZ  ) plans to launch 2 cryptocurrency-focused exchange-traded funds (ETFs), becoming the latest institutional entrant into the sector while Wall Street waits for the U.S. Securities and Exchange Commission to make a decision on numerous Bitcoin ETF applications. According to a filing with the SEC, the Invesco Galaxy Crypto Economy ETF will track the investment results of the Alerian Galaxy Global Cryptocurrency-Focused Blockchain Index, and the Galaxy Blockchain ETF will track the Alerian Galaxy Global Blockchain Index. About 85% of the Invesco Galaxy Blockchain Economy ETF and the Invesco Galaxy Crypto Economy ETF will be in crypto-linked equities, while the rest will be in other trusts and funds that hold crypto assets. Atlanta-based Invesco, which has $1.5 trillion in assets, could avoid the SEC's ETF uncertainty by investing indirectly in cryptocurrency through its 2 new ETFs.

Crypto prices edged down to $1.575 trillion this week as trading remained range-bound. For the majors, Uniswap (UNI), Dogecoin (DOGE), and Polkadot (DOT) posted outsized losses, while Bitcoin rose slightly. In the top 100, the biggest losers were Internet Protocol (ICP), down 40%, SushiSwap (SUSHI), down 27%, and Synthetix (SNX), down 26%. The biggest gainers were Amp (AMP), up 27%, Quant (QNT), up 26%, and Theta Fuel (TFUEL), up 19%. Next week traders will see if Bitcoin can break the key $40,000 level.

The author owns a small amount of BTC.