How the add-ons migration (2020 > 2024) will work

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Owned MSFS 2020 Content

For any content you purchased outside of the simulator, the Community Folder will continue to work as it did in MSFS 2020. Any content in your MSFS 2020 Community Folder can simply be copied over to the new MSFS 2024 Community Folder, and the vast majority of that content should work in MSFS 2024.

For any content you purchased in the Marketplace in MSFS 2020, that content will show up as owned in the Content Manager (in MSFS 2024 called “My Library”) at launch for you to use in MSFS 2024, and the vast majority of that content should work in MSFS 2024. This availability does not require developers to sign off on their content.

Owned MSFS 2020 Content that has been Upgraded for MSFS 2024

For content you already purchased in MSFS 2020, upgrades to Microsoft-produced content (e.g. Reno Air Races, Local Legends, Famous Flyers, Expert Series) will be free to you.

For content you already purchased in MSFS 2020, upgrades to all other (non-Microsoft) developers’ content will have two potential options based on each developer’s discretion:
1. The developer can make the upgrade free.
2. The developer can choose to charge a fee for the upgrade.

Non-owned Content: Availability in the MSFS 2024 Marketplace

For any content, including existing MSFS 2020 content, developers must sign off that the content is functional for it to appear for sale in the Marketplace.

Upgraded = built with the MSFS 2024 SDK, Not Upgraded = built with the MSFS 2020 SDK

Source: https://www.flightsimulator.com/microsoft-flight-simulator-2024-faq/