Lagrange.OneBot.DatabaseShift --help
Lagrange.OneBot.DatabaseShift --in /path/to/lagrange-0.db
The output Realm database folder will be located at /path/to/lagrange-0-db
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Checkout the branch of the submodule Lagrange.OneBot to the corresponding branch that uses LiteDB, modify RealmMessageRecord to ensure all desired fields are stored, then compile and run it.