If you have the money burning a hole in your pocket then update the cartography, but unless you're planning on relying upon the POI information I wouldn't worry too much. The reality is that due to the time lag between the roads survey data being collected and the publication of the cartography, you will always find something that's incorrect somewhere, even if you do update the device. While you're unlikely to run into serious difficulties with roads having changed, be aware that access restrictions or one-way systems may have been implemented in cities that aren't reflected in your version of the cartography so don't blindly follow the navigation instructions.
Do make sure that you don't have any speedcam data loaded for either France or Switzerland as it's an offence to use GPS-based warning systems in both those countries. Also make sure you keep within the limits in Switzerland as the fines for even a minor infraction are now very high. For a significant infraction they are eye-watering, and the Swiss authorities will chase you through the UK courts for unpaid fines.
Have a great trip!
