Package has unversioned properties but mapping file is missing, can't serialize

[4sval]

Packages with unversioned properties are expected for UE5+ games, but there are solutions to keep reading them with FModel.
Using one of the dumpers below, you can generate a mapping file containing a schema of your game's classes, structs, and enums. This schema is subject to change after every new update, so, should be regenerated after each one in order to avoid errors.

Dumpers you can use:

• https://github.com/Encryqed/Dumper-7
• https://github.com/UE4SS-RE/RE-UE4SS
• https://github.com/trumank/jmap

Read their READMEs for more information on how to use them.

Once the mapping file is generated, open your FModel settings and set a local mapping file like so.

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Important

If you did not understand the instructions above, please join the Discord and check the #game-compatibility channel for either:

• a thread about your specific game, that includes a mapping file
• a thread about another game running on the same UE version, with a mapping file attached. It won't contains the custom classes, structs, and enums your specific game has, so expect various errors.

You can also look at UEDB, Unreal-Mappings-Archive, or any other places where mapping files may be shared.