I purchased, (again) D X O nik collection, late last year.
Am now receiving regular, (whenever i click photo effeX), an option to ‘upgrade’.
Then directed to option to pay for 100.00 upgrade.
I assumed an update would be free.
Esp. since i have not had the software for a year.
Try your luck with support.dxo.com
DxO has no such policy of offering free upgrades for a year. That was an incorrect assumption. DxO has a different release cycle: provide a major update for sale, then update it for free until the next major release is offered for sale (usually a year later in the case of the Nik Collection). There are pros and cons. The new upgrade for sale is offered at a significant discount to anyone owning a registered license for a previous version. This means you don’t have to pay once a year for continuous updates: you can update at a discount much less often if you want. It also means that if you’ve owned a license for less than a year, and a new major release is offered for sale (and you want it), you pay the same amount for it whether you buy now or wait a while.
The upgrade notices in the software should stop after about a month. I don’t know if they can be turned off.