TalkTalk has today started giving out free upgrades to all four million of its customers – including free Sky Sports for its TV users – to "say thank you" for sticking with the firm after a data hack left nearly 157,000 account holders' personal details exposed.

Last month, the embattled provider announced the sweetener deal for all its customers – not just those whose personal or banking details were accessed. Today it unveiled more details of what you can get (though there are still a few things it hasn't clarified) and started offering the upgrades.

If you're a TalkTalk customer, even if you joined after the hack, you've until 31 December to claim your upgrade – you can do so by calling 0800 230 0403 or via live chat today, or via your online account from Wednesday 9 December. Here's what you can choose from:

1) TV channels – open to existing TV customers only

Only those who currently have TalkTalk TV can opt for this one for free. You can choose from one of the following TV boost packages – films, kids, entertainment or Sky Sports, which will be free for three months.

This upgrade would normally cost between £5/month and £30/month depending on the channels.

2) A 12mth mobile Simopen to all customers

Any current TalkTalk customer can choose this option – a 12-month mobile Sim. It's very much a value option though, with a monthly allowance of 100 minutes, 250 texts and 200MB of 3G data.

If you go close to your allowance, it'll send you a text message. If you go over, you'll be charged out-of-bundle fees, which are 40p/minute to call landlines and mobiles, 15p per text message and 15p per MB of data. TalkTalk Mobile piggybacks on the Vodafone network.

Normally this Sim costs £5/month.

3) Unlimited UK landline and mobile calls – open to broadband and home phone customers

For those who already have a TalkTalk landline and broadband, it's offering calls to mobiles and 01, 02 and 03 numbers (excludes 084/087/09 as well as 118 numbers) free for 12 months.

While it's 'unlimited', TalkTalk does operate a 'fair use policy' of 1,800 minutes per month (30 hours). Calls are free for the first 60 minutes only, so if you pick this option, make sure you hang-up and redial within the first 60 minutes or you'll be charged the standard rate of 11.5p/minute for landlines and mobiles. Some non-inclusive calls may be subject to a connection charge of 17p too.

This calls package normally costs £7.50/month.

4) A broadband and wi-fi health check – open to broadband customers

If you already have TalkTalk broadband, you can arrange for an engineer to visit your property to check your broadband and wi-fi and improve their performance for free. The engineers operate between Monday and Friday 7am-8pm and on Saturdays between 7am-6pm.

If an issue is found, the engineer will attempt to fix it there and then. However TalkTalk says that if there's a problem with the line, it'll need to refer the issue to BT Openreach. We asked whether engineers would attempt to up-sell to customers and TalkTalk's confirmed they won't.

The broadband and wi-fi check usually costs £65 for a visit.

Will I automatically be charged for the upgrades after the free period ends?

TalkTalk says there's no ongoing charge associated with any of the upgrade options above. So when the free TV, mobile Sim or calls package ends, it'll be automatically removed from your account and you won't be charged in future.

What if I don't want an upgrade, can I cancel my contract instead?

We asked TalkTalk what would happen if customers did not want to upgrade and asked to cancel their contracts instead. As it's told us before, it says only those who can prove they've lost out financially as a result of the hack will be able to leave penalty-free. See the Four million TalkTalk customers to get free upgrade and the TalkTalk website hack MSE news stories for more information.

TalkTalk customers given free upgrade including Sky Sports or a 12mth Sim following data hack
TalkTalk unveils its free upgrade options for four million customers

All customers also get a free improved security package

TalkTalk also says it's created a new bundle of 'online and telephone security features', designed to improve protection from scammers, malware and cold callers. This includes caller display, voicemail (so unknown callers can leave a message), last caller barring (so you can block callers you don't like), and anonymous caller reject.

Again, the provider says customers can activate the features via the live chat service or by calling 0800 230 0403 or you can activate it online via your account from 9 December.

'A free upgrade... to say thank you'

TalkTalk is sending out emails and letters from today listing the free upgrade options available to customers. On the web page announcing the changes it says the upgrades are "our way of saying thank you for standing by us during the recent cyber attack".