Some time ago I bought some satoshis and installed Electrum v3.x on a fresh install of Windows 10 on a spare laptop, to use as a cold storage setup. This is always off line and only ever used to sign transactions.

I upgraded to a watching version of Electrum to 4.x on an online pc.

The question is, do I ever need to upgrade Electrum on the cold storage laptop, assuming the laptop continues to work?

[This version of Electrum is too old to open this wallet.]

I have a wallet which was created with v3.8 and in use with v4.1.5.

I installed v4.2 and opened the wallet, and it looked OK. But when I try to open it with v4.1.5 it fails with error message:

This version of Electrum is too old to open this wallet.
(highest supported storage version: 18, version of this file: 44)

Is this an expected behaviour? Am I now forced to use 4.2 forever? I didn't see any warnings about this.

I could recreate the wallet for 4.1.5 using the seed phrase, but that loses the transaction descriptions.

[Certificates]

On Windows 7 I downloaded GPG4WIN to verify the latest Electrum 4.2 download.

I followed the procedure given on the Electrum Download page => https://bitzuma.com/posts/how-to-verify-an-electrum-download-on-windows/

Having got GPG4WIN verified, I run Kleopatra and do a Lookup on Server for the key for ThamasV = 0x2bd5824b7f9470e6

It does find an entry for ThomasV, which I import. However, the result of the import is
Certificates
Total number processed: 0
Imported: 0

When I decrypt/verify using electrum-4.2.0.exe.asc the result is:

Verified ‘electrum-4.2.0.exe’ with ‘electrum-4.2.0.exe.asc’: 3 signatures could not be verified.

It then gives options for 3 signatures to search for or import the 3 signatures.. Search gives no results and I don't have files to import from.

What am I doing wrong?

Will the seed phrase (12 words) from a version 3.x wallet successfully create the private keys with Electrum V4.x ?

I know it's very unlikely, but there is nothing to stop a hacker from generating wallets using the 12 word Electrum seeds, to steal bitcoins.

With luck, they might generate a valid wallet, which had been previously created, and which contains bitcoins

Similarly, a non malicious user might accidentally generate a duplicate wallet.

Should users be encouraged to add some random words to reduce these (admittedly minuscule) risk?

Which is a more secure Electrum setup?

Airgapped on Windows or Tails?

Is the order of the 12 words in the seed phrase important?

Coinfloor clients are all now transferred to CoinCorner.

To me, this seems a retrograde step as CoinCorner's website does not have any of the market tools of CoinFloor. CoinCorner seems like an expensive MickeyMouse option.

Does anyone have an opinion?

Can anyone offer any recommendations for a good UK based exchange offering competitive rates, and with decent market tools?

Is it possible to convert a 'normal' electrum wallet to multi-sig?

Also, is multi-sig more secure?

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?

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?

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.