WE CAN DO THIS FOR YOU. See service at https://wpfixit.com/product/wordpress-support/
Although having latest WordPress is good idea, but sometime you may wish to back to earlier version of WordPress installation. This can happen when your plugins do not work with new version and you have majortheme issues.
Well, downgrade a new version of WordPress to older version is a easy task and that same as upgrading a WordPress to newer version.
- Make full back up of your site whatever you do first make backup of WordPress folder and database. You need to have access to your site control panel using ftp program such as Filezilla make a copy of all WordPress Platform files. These are located in the root directory of your host or the root directory of the location you installed WordPress.
- Delete wp-admin and wp-includes folder which are located in your default host directory.
- Get and download the old version of WordPress that you need from wordpress.org release-archive.
- Unzip your desired version of WordPress and overwrite all files EXCEPT wp-content folder to your website by using ftp program.
- Go to your site admin area this time you wont see WordPress admin login page. Instead you will notice a message that say WordPress Database needs to upgraded current WordPress to new one!!. do not worry, just click OK and you will then see the admin login box.
- Login to admin area and HAVE FUN!
Everything will be fine and you can enjoy old WordPress installation on new on WordPress.