Sky Set Top Box

Answering the question you asked, the response is "Yes, up to a point".

You can change out your Sky box for another at anytime, but the "new" box has to be paired with your card and Sky account.

Have your card number and the box's serial number written down and ring Sky Customer Services.

I assume that the replacement box is the same spec and facilities as the one being replaced.

I think he's looking for an upgrade from SD to HD

I assume your TV doesn’t have a satellite tuner then. OOI, what do these boxes have over the satellite tuner built into most TVs?

Pretty easy. But the Sky sub is a bit more for HD.

But he has one of the freesatfromsky cards ... oh dear, apparently discontinued in 2021

They arent built into most TVs, certainly at the budget end. Its pretty much the same thing, the interface is different again, but they receive the same channels as all other boxes.

You only needed a card for the free to air channels if you had a sky box.

No card needed for the same free to air channels if you had a Freesat box. Freesat has nothing to do with Sky.

No card needed for the same free to air channels if you had A.N.Other box.

It's my opinion that when UK Freesat was launched Sky deliberately choose the name "Freesat from Sky" to reinforce the belief by many that if you wanted UK TV via satellite the only player was Sky.

Freesat was launched in 2008. Basically it was just a 7 day epg service for many of the Free to Air UK channels that already could be received from the Astra satellite cluster at 28.2E, and without a subscription and without a card.

I have a Humax Freesat recorder and it receives free HD channels no problem. Don't expect to get subscription channels without subscribing though.

My Humax Freesat box (obtained from Freecycle) shows 7-day EPG on all Freesat channels, but not on non-Freesat channels.

Nevertheless, Sky does charge a subscription premium for receipt of HD channels. Recently, there has been some controversy about SD channels being discontinued.

True enough, at one time there were a handful of channels which were FTV rather than FTA (i.e. needed a free card to decrypt them) some would say the sky EPG and handling of retunes is superior.

They have separate EPGs but use the same programme streams

Of course

I have a non-sky, non-freesat linux setup, which also includes 19.2E which no longer adds any channels of value (other than the occasional 4K test channel)

Interesting - I see that very few Samsung TVs have it; most LGs do.