Problem statement
After upgrading NodeJS runtime version from 12 to 16, there are connection issues from MySQL database via the application. Reverting this back to NodeJS 12 through Tenant Settings > Advanced > Extensibility > Runtime but NodeJS 12 is no longer available in the drop-down list.
Solution
Ensure that you use the same module version across node runtimes, you can change require("mysql")
to require("mysql@2.7.0")
in your DB scripts.