# Converting thousands of tables from UTF8(utf8mb3) to utf8mb4 when upgrading from 5.7 to 8.0

**URL:** <https://forums.percona.com/t/converting-thousands-of-tables-from-utf8-utf8mb3-to-utf8mb4-when-upgrading-from-5-7-to-8-0/12286>\
**Category:** Percona Server for MySQL 5.7\
**Created:** [September 24, 2021, 4:04pm UTC](https://forums.percona.com/t/converting-thousands-of-tables-from-utf8-utf8mb3-to-utf8mb4-when-upgrading-from-5-7-to-8-0/12286 "2021-09-24T16:04:02Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![ipcmlr](https://avatars.discourse-cdn.com/v4/letter/i/df705f/32.png) [@ipcmlr](https://forums.percona.com/u/ipcmlr)\
**Post date:** [September 24, 2021, 4:04pm UTC](https://forums.percona.com/t/converting-thousands-of-tables-from-utf8-utf8mb3-to-utf8mb4-when-upgrading-from-5-7-to-8-0/12286/1 "2021-09-24T16:04:03Z")

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Hi everyone,  
I am getting a warning when running prechecks for the 5.7 to 8.0 upgrade regarding tables with UTF8(utf8mb3).  
Problem is there are thousands of tables with utf8mb3 that I have to convert.  
Is there a utility for converting databases and tables to the newer utf8mb4?

I also find it weird that when I create a database in MySQL8.0 that UTF8 is still utf8mb3 not utf8mb4.

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<div class="post-metadata">

**Author:** ![matthewb](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/matthewb/32/34_2.png) [@matthewb](https://forums.percona.com/u/matthewb)\
**Post date:** [September 24, 2021, 5:29pm UTC](https://forums.percona.com/t/converting-thousands-of-tables-from-utf8-utf8mb3-to-utf8mb4-when-upgrading-from-5-7-to-8-0/12286/2 "2021-09-24T17:29:17Z")

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utf8mb4 is the current standard in MySQL 8. “UTF8” has always been an issue in MySQL, and always been 3-bytes. Instead of changing what “UTF8” means to be 4-bytes, utf8mb4 was introduce in 5.7.

Since you are getting ‘warnings’, then there really isn’t much you need to do. The tables will still function fine. You can use pt-online-schema change to power through all the updates, or just bite the bullet and do each table one at a time using traditional ALTER TABLE.