Williams is keeping its car for the 2024 season very close to its chest.
The British team actually 'launched' for the new year earlier this week in New York - but it was actually just the 2023 car with the new livery for 2024.
Germany's Auto Motor und Sport thinks the big secret is the 2024 car's rear suspension.
"We have been working on the new car since March," said Williams boss James Vowles, confirming the early development start-date for the new year.
The 2023 car's last update was then at Silverstone - in July.
"The aerodynamicists have chosen a completely new approach (for 2024) in terms of concept," Auto Motor und Sport correspondent Michael Schmidt said.
Alex Albon confirmed: "The new car feels completely different in the simulator."
Boss Vowles thinks it's worth the risk. "If we fail, I'll take that on," he vowed. "If we don't take a new path, we'll stay where this team has been for the last ten years."
And the big secret of the 'new path'? It could be the fundamental change from pullrod to Red Bull-like pushrod rear suspension.
"We don't want to reveal what we're doing at the back yet," Vowles admits, while other sources suggest the same secret might be shared by Williams' engine supplier, Mercedes.