Now, in the last two versions i'm absolutely not able to connect to the database, because metabase do not use it anymore. I red it, something was changed with the dirvers, but currently i can't update metabase, because it will not work with the IBM iSeries.
You need to use convert the driver into the modular, which is being used since 0.32 https://github.com/metabase/metabase/wiki/Writing-A-Driver
Drivers are now located in /modules and will automatically extract those drivers to the environment variable MB_PLUGINS_DIR, and read any custom drivers in that path too.