An online flyer for the new car, which is understood to be official, confirms the date of the premiere of Ferrari's "149M project".
The current generation of California has the official internal code of F149; the additional M mentioned in the teaser is thought to mean Modificado.
Previously, Ferrari has used the M designation on models that have been upgraded or heavily revised. For example, the Ferrari 360 had the internal denomination of F136. The model that succeeded it, the F430, bore the identifier F136M.
Consequently it's likely the model set to be unveiled is a dramatically revised version of the current California. It's understood that the biggest change for the new California will be the ushering in of turbocharging to mainstream Ferraris.
The latest iteration of Ferrari's convertible model is set to be powered by a 552bhp version of a new Ferrari-designed and built twin-turbo 3.8-litre V8 engine, first used in the Maserati Quattroporte and Ghibli models.