As per your question, usage -AND- upgrades are two different things.
1) You can use the programme for ‘Lifetime’.
Recently, A LOT of cies restrict usage for 6mo, 12mo, etc. Meaning even if you paid for the sw, you won’t be able to use it after the stipulated period.
This is new thing … from the past ~2-3Y, a new restriction more & more developers are applying to force us to buy the same sw every year or so !!
2) Upgrades are the period of time you’ll be able to apply newer versions.
So here, even though it’s a promotion, the cie is offering to give free upgrades for 6mo.
It’s very generous, most cies do not offer any upgrades at all for a free promo.
You can apply upgrades for 6mo w-out penalty, but will be able to use the programme indefinitely, as there is not cut off date.
If you want to rcv further -upgrades- past the 6mo free promo, they are offering an extension of 2Y
for a modest amount.
Hope this helps,