# phpman > ri > ActiveRecord::Migration::Compatibility::V4

## [ActiveRecord::Migration::Compatibility::V42](https://www.chedong.com/phpMan.php/perldoc/ActiveRecord%3A%3AMigration%3A%3ACompatibility%3A%3AV42/markdown) < [ActiveRecord::Migration::Compatibility::V50](https://www.chedong.com/phpMan.php/perldoc/ActiveRecord%3A%3AMigration%3A%3ACompatibility%3A%3AV50/markdown)

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