I carried out a quick test, but I don't understand the results.

With Version 3.3.8 I created a new test wallet, noted the seed phrase, and exported the private keys as a CSV file.

With V 4.0.9 I created a new test wallet, used the above seed phrase, and exported the private keys as a CSV file.

In the resulting CSV files, V 3.3.8 exported 26 addresses and private keys. However, V 4.0.9 exported 30 addresses and private keys.

Comparing the 2 CSV files in Excel, the 26 addresses and private keys were identical in both versions, but V 4.0.9 generated 4 extra addresses and private keys.

Why the extra 4?

Forgive me lack of understanding, but if in V 3.3.8 I generate several new addresses, after the original 26, would new private keys result?

If so, and if I used the seed phrase to restore a wallet, how would it know that new private keys had been created?

Finally, can I assume that because v 4.0.9 generates 4 new private keys, then restoring a seed phrase from a V 4.0.9 wallet to recreate in V 3.3.8, then effectively, 4 private keys, and their associated addresses and bitcoins, would be lost?

Thanks for the clarification.

As a follow on, let's suppose I stay with v3.3.8 and my airgap PC dies. I will have to start again by installing a new version on both the airgap and watching, but will my existing seed phrase still work? Or should I print off my private keys and sweep them in?

I've set up Electrum on an airgap computer and a watching wallet on my normal PC.

The versions are 3.3.8, but I see that there's a newer version 4.0.9.

I'd rather not touch the airgap PC, so can I run 4.0.9 on the watching PC and stick with 3.3.8 on the airgap?

Indeed, should I stick with 3.3.8?

I suppose the biggest risk to anyone, especially individuals, holding BTC, are the Governments.

While they can't easily shut down the blockchain, Governments could  shut down exchanges. Likewise miners, although they would have to act together.

Two mitigating factors:

1. Big companies are major contributors to political parties, so big money talks.

2. Countries like Iran, Russia, North Korea and others, will step into the mining arena.

For us smaller fry, given that BTC supports decentralised protocols, might we see decentralised exchanges? Or exchanges operating in laxer jurisdictions, like The Caribbean, African countries, or nations unfriendly to US/Europe/UK?

Most likely, Governments will try and milk taxes from us all! Beware of Mr Sunak

There was an item in the Financial Times pooh-poohing the Citibank article.

Well, they would, wouldn't they?

There was quite a strong US emphasis, but I wonder how long it will take for UK and European corporates to jump aboard?

This is a very interesting, balanced and serious article by Citibank.

https://www.citivelocity.com/citigps/bitcoin/

IMHO it is well worth a read.

I just received an email from "Electrum Official" <support@electrum.org> saying:

------------
New wallet with updated encrypted vault!  Cold Storage 
Keep your private keys offline, and go online with a watching-only wallet.  Add-ons 
Electrum supports third-party plugins: Multisig services, Hardware wallets, etc.  Instant On 
Electrum is fast, because it uses servers that index the Bitcoin blockchain.  Download update 

Electrum v.4.0.9-1 is available for download 
 ©  Electrum  2021 
Electrum Technologies GmbH 
Paul-Lincke-Ufer 8d | 10999 Berlin | Germany   
-----------

Is this genuine?

Thanks to all for the superb advice.

One final question, is whole disk encryption recommended in addition to wallet encryption?


I believe that an air gap Electrum wallet is the best solution for me.

pooya87, that's an excellent strategy...if only I had 10BTC 

Seriously though, can you please explain why you favour the paper wallet for long term HODL when this WiKi https://en.bitcoin.it/wiki/Paper_wallet#:~:text=A%20paper%20wallet%20is%20the,and%20should%20not%20be%20used. so strongly discourages it?

If I do generate a paper wallet, would this https://github.com/pointbiz/bitaddress.org be a suitable tool?

I would say that I'm a newbie/average user.

But the steps in https://electrum.readthedocs.io/en/latest/coldstorage.html#coldstorage seem to be well described. Following it step by step appears to be straightforward. Receiving BTC is the same whether Electrum is air-gapped or not.

Because of the extra step of signing the transaction on the air gapped wallet, it's not as easy nor as quick to spend BTC, as using a hardware wallet, or a non-airgap setup.

But I think if we are considering an air gap solution, it's because we are dealing with non-trivial value. In which case, care and time are amply repaid, and outweigh speed or convenience.

Thanks for those responses.

I am not clear if the Electrum seed phrase can be used directly in other BIP39 wallets.

I entered the Electrum seed for a wallet I just created in "The Electrum Mnemonic Seed Tester" tool, and it gives the same private keys as created in the wallet.

So, if I wanted to swap to another wallet (not Electrum) would I need to use the above tool as an intermediate step?

Also, if I went down the Electrum air gap route I would go through the following steps:

1. Prepare the air gap pc using a dedicated laptop, with a LAN, WiFi, Bluetooth etc disabled in the BIOS.

2. Instal a fresh copy of Windows 10 from a Microsoft DVD onto the laptop, checking that all networking is disabled.

3. On an online PC, do virus and malware checks, format a USB and download Electrum onto the USB, checking the signature.

4. Transfer the USB to the air gap laptop, and instal, with wallet encryption.

Would this be secure enough?

Portability is not high on my list.

The cost of a hardware wallet is not excessive, given the price of bitcoins. I'm looking to choose an approach.

I've read about the Electrum setup of a watching wallet online combined with a wallet holding the private keys, on an air-gapped computer.

If this is correctly set up, is the hardware wallet inherently more secure?

For example, if I compare the 2 approaches, how do the 2 setups compare if:

- Hardware failure?

- Malicious attacks?

While the hardware vendor client database can be hacked, allowing criminals to come knocking on my door, can the same happen with Electrum?

Also, looking longer term, what would be the consequences of developers ceasing to maintain Electrum?

Should I also export my private keys, in addition to the seed phrase (with appropriate safety and storage precautions)?

What other criteria should I consider?

I'd appreciate any advice from the experts.