Hi,
> can I just copy the old mysql files into the reinstallation?
No.
The transfer of databases between different versions of MySQL or MariaDB should be performed by EXPORT / IMPORT of SQL files using phpMyAdmin or a similiar tools of your choice. Do not copy the data folder between different versions of MYSQL or MariaDB.
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Documentation Apache -
Documentation PHP -
Documentation MySQL -
Wampserver install files & addons