Using APT Repositories

1. Reconfigure MySQL and choose the older version:

shell> sudo dpkg-reconfigure mysql-apt-config

1. Run apt-get update:

shell> sudo apt-get update

1. Remove the current version:

shell> sudo apt-get remove mysql-community-server mysql-client mysql-common mysql-community-client mysql-community-client-core mysql-community-server mysql-community-server-core -y

shell> sudo apt-get autoremove

1. Install the older version (autoselected since you have reconfigured):

shell> sudo apt-get install -y mysql-server