# Migrating from NC 15 to 21

**URL:** <https://help.nextcloud.com/t/migrating-from-nc-15-to-21/119490>\
**Category:** ℹ️ Support\
**Tags:** update\_problems\
**Created:** [July 3, 2021, 2:27pm UTC](https://help.nextcloud.com/t/migrating-from-nc-15-to-21/119490 "2021-07-03T14:27:07Z")\
**Posts on this page:** 1\
**Showing post:** 7

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**Author:** ![Bernie\_O](https://help.nextcloud.com/user_avatar/help.nextcloud.com/bernie_o/32/40181_2.png) [@Bernie\_O](https://help.nextcloud.com/u/Bernie_O)\
**Post date:** [July 5, 2021, 5:33am UTC](https://help.nextcloud.com/t/migrating-from-nc-15-to-21/119490/7 "2021-07-05T05:33:12Z")

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> [@James\_O\_Stanworth](#):
>
> I also have some apps e.g., calendar - will this “find” the data if I enable them again?

calendar data is stored in the database (as also data from some other apps is). So, if you only copy the files and do the rest from scratch, calendar data will be lost.

You could use [calcardbackup](https://help.nextcloud.com/t/calcardbackup-bash-script-to-backup-nextcloud-calendars-and-addressbooks-as-ics-vcf-files/11978) to export calendars (and addressbooks) from the old version and then reimport the calendars to the new version (preferrebly with the help of a client). This approach is not practicable with a large user base, though.

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_[View the full topic](https://help.nextcloud.com/t/migrating-from-nc-15-to-21/119490)._