Quote Originally Posted by DrByte View Post
Just to be certain of no clash, and no accidental firing that's overwriting the aim changes, try making the same varchar(32) change to the echeck module.

Or just use the new authnet files from v1.5.5d which now has the varchar(32) changes built-in ;)
I am happy to report that after installing v1.5.5d the string varchar(32) appears permanently as the type for the transaction_id for authorizenet in mariadb. Also, after changing back to STRICT_TRANS_TABLES in my.cnf and restarting mariadb - transactions now go through with out error.

Thank you DrByte and all the Zen Cart programmers!