Maurice LaMarche succeeded Adams halfway through the previous series, Gadget Boy & Heather, and one must assume this might've been because Adams was in declining health. The 60's icon would pass away in 2005. Anyway, Gadget is now a Lieutenant, and while his perpetual pre-teen niece, Penny, is still around, her dog, Brain, isn't, having retired from field duty due to some trauma from repeatedly being mistaken for enemy agents, a running gag in the original series. Chief Quimby and Gadget now work for a French intelligence agency, but Dr. Claw is still the main villain. The Gadgetinis, Digit & Fidgit, were created by Penny to serve as her uncle's assistants. Kind of like doubling down on the old gags, no?
Let's take a look at the series opener.
Even aliens can be mistaken. Reportedly, there's a reboot of the franchise, which is airing on Netflix here in the US.