If you downloaded the update manually, then you will need to copy everything in your save folder from the old version over to the save folder in the new version. You can find the save folder here: Didnapper 2/www/save/
If you want some more detailed and quicker help, feel free to ask in our public Discord server, where both Didnapper developers and other players are nearly always available: discord.gg/xXDgYPV