The four most famous international exchanges:

Binance INTL	OKX INTL	Gate.io INTL	Huobi INTL
China Line　APP DL	China Line　APP DL	China Line　APP DL	China Line　APP DL

Note: The above exchange logo is the official website registration link, and the text is the APP download link.

John Newbery is a Bitcoin Core developer, Chaincode
Labs engineer. This article is the future development path of Bitcoin shared by him on Twitter. He believes that in 2020, technologies such as Lightning Network, Schnorr/Taproot, Payjoin, and miniscript will gain more development.

Image source: Pixabay

The end of a decade is a good time to look back on history and marvel at how far Bitcoin has come since Satoshi Nakamoto gave us a glimpse of the Bitcoin white paper in 2008. Of course, this naturally leads us to look forward to what will happen in the next few years.

Some of what I think is where Bitcoin is headed in the next few years. If you feel it is incorrect, then please tell me why I am wrong and what is wrong!

Lightning Network

Lightning Network Protocol Team (Blockstream’s C-lighting, Acinq’s eclair, Lightning
Labs’ LND) and the robust Lightning Network will continue to iterate rapidly.

All implementations now support basic multipath payments. We will provide better support for this, as well as dual-funding, splice-in and splice-out.

Taken together, these technologies will make lightning channels and liquidity management easier. They will be executed automatically and the user experience will be greatly improved.

The Lightning Network infrastructure will be improved. For example, Bitfinex has recently supported Lightning Network Bitcoin deposits and withdrawals. All other exchanges, merchant service providers, custodians, and wallets will follow or be left behind.

We will see more Lightning Network wallets: non-custodial hybrid wallets; outsourced routing self-hosted wallets; fully self-managed wallets. This is a completely new area and there will be a lot of experimental products. Different teams will find different spots. Like Muun, Breez, Phoenix, Zap, Bluewallet, etc., these wallets are experimenting with different models.

Tools for Lightning Network developers will also be improved. A little over a year ago, when we were running Lightning applications, developers spent a lot of time setting up their Lightning development environments.

Now, via Polar developed by Jamal James
, Lightning Network application developers can set up a test environment with just a few clicks. More and better tools will continue to appear. With these better tools, we will see faster innovation at the application layer. ZEBEDEE and Satoshi's
Games and other teams we haven’t heard of yet will bring us new and unexpected exciting Lightning experiences.

Schnorr/Taproot

The Schnorr/Taproot soft fork will be activated in 2020 or 2021. This will provide huge improvements in fungibility, privacy, scalability and functionality.
For an overview of the benefits, watch the Optech executive’s presentation here: Link

This will upgrade the Lightning Network from HTLC to Payment Points.
This is a huge improvement to privacy and payment decorrelation, and allows for "fixed payments" with proof of payment - another huge improvement in the usability of the Lightning Network. (Related to Payment
Points) for more information (see)

Even better, the opening and closing of Lightning channels looks the same as payments to a single pubkey. The same goes for payments to n-k pubkey thresholds.
This is great for fungibility, privacy, and scalability.

In fact, with schnorr/taproot, there is little downside to blocking UTXOs using high-level scripts rather than individual pubkey outputs.

Cold storage UTXOs will be k-of-n key trees of n signatures, and all hot wallet UTXOs will be stored in channels (with splicing-out for making on-chain payments).
When transactions hit the entire chain, they will look like any other single pubkey/signature payment.

Payments to the wallet will be made directly to the channel's open output (thanks to @esneider for pointing this out to me). There will be no concepts of on-chain balance and intra-channel balance.
Just a unified balance can be used for Lightning Network or on-chain payments.

PayJoin protocol

The wallet team will collaborate on the PayJoin payment protocol. A large number of on-chain transactions will be 2-input-2-output transactions, greatly improving fungibility and privacy, and resisting on-chain analysis.

The input of these PayJoin transactions may be channel splicing and the output may be channel opening, but there is no way to tell by looking at the blockchain.

Eventually, we will have cross-input signature aggregation, which means these PayJoin transactions will have only one signature and be "cheaper" than regular change-generated transactions.

Larger coinjoins transactions will still be cheaper. The advanced PayJoin payment protocol can even batch multiple payments to the same merchant/exchange and use only one signature.

We will get SIGHASH_NOINPUT or SIGHASH_ANYPREVOUT, making eltoo possible and blurring the line between Layer 1 and Layer 2.

This will make the Lightning Network more usable and allow for more advanced Layer 2 contracts (such as channel factories).

miniscript

All these advanced features will require greater wallet interoperability. At this time miniscript is needed.

With miniscript, wallets will eventually be able to contract with each other without the need for pre-templated scripts (as is currently the case with the Lightning Network). This wallet interoperability will allow for layer
2 Contracts for faster innovation.

OP_CTV or other contract-enabled opcodes will activate, allowing the use of richer Layer 2 constructs such as joinpools.

Together with Taproot and SIGHASH_NOINPUT we will become very rich and private off-chain contracts will be possible.

Some of these things will happen in 2020, some of them will take longer, but they're all heading in the same direction: putting blockchain to work where it does well (h/t Andrew
Poesltra).

That is: the blockchain allows nodes to reach an agreed-upon ledger state, while contracts and functionality move up to Layer 2. Doing so is cheaper, more secure, more private, and allows for faster innovation.

It's all inevitable, but it wouldn't have happened without the efforts of many people and the creativity of many minds. Developers, researchers, businesses and users still have a lot of work to do.