The save files are stored within the game folder itself. The RPGMaker is a very ancient and simple game engine. If you still got the game folder of the previous version of the game, you can just go in there, the "www" folder, and replace the "save"-folder in the new update with the old one.
I assume you use the itch client, then? Well, you can check the folder in which itch stores all the games you download. I don't know which file path you picked when you installed the client, the default is C:/Users/[USERNAME]/AppData/Local/itch. You can go there and check for the "small-on-top"-folder. Go in there, and if you got two game folders inside (one numbered 0.24 and one 0.24.1), you're lucky. That means the itch client is simply linked to the newer version, and your save files are in the 0.24 folder. If there's only the 0.24.1 folder, then I'm afraid itch replaced your old game files entirely with the new ones. And since the save files are stored inside the game folder directly, that includes your old saves.
Side note, if you wanna use one of the prepackaged save files, you can return to the Gloomy Forest, to the ID machine at the entrance to Bangers club, and change your main character's name.