CiviHosting has sent a notice to all their customers that they are upgrading all their servers to MySQL 5.7, despite their acknowledgement that CiviCRM prior to version 4.7.7 "may fail". They plan on performing this upgrade in one week, August 17.
For those customers that are not able to upgrade to a compatible CiviCRM version at this time (due to various customizations), what are the various issues that can be expected?
I know of the lock name length issue (When upgrading from 4.7.7 to 4.7.8 I get error "Specified key was too long") which appears to be an upgrade process issue. (Does this problem extend back to prior to 4.7?)
What else is there to be concerned with, particularly with versions 4.4.x, 4.5.x, and 4.6,x?