I am trying to set up OpenEMM on an Ubuntu 16 AWS server, but I cannot get MySQL 5.6 onto the server, as Oracle has discontinued support for MySQL 5.6 on Ubuntu 16 (but not earlier versions of Ubuntu, apparently). What should I do? I tried adding the Ubuntu 14 repository and downloading MySQL 5.6 from there, but that version of MySQL would not run. The only functional version of MySQL I have been able to obtain is 5.7, but the manual for OpenEMM specifically says not to use 5.7. What should I do?