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Author: Migaroez

17/umbraco-cms/extending/single-block-migration.md

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+V17 introduces the single block property editor. It's purpose is to replace the "single mode" option that exists in the blocklist property editor. This is part off the more general effort to ensure type consistency within core propertyeditors.
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+### Optional migration
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+### Extending the migration
+If you have a non core propertyEditor that allows nesting content within it and stores that content within it's own value, then you will need to extend the migration. To do this you will need create and register a class that implements `ITypedSingleBlockListProcessor`
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