Install on debian 9 (and MariaDB 10.1.23)

Hi to all,

I'm tring to install CWIS 4 on a Debian 9 with MariaDB 10.1.23, PHP 7.0.21, Apache 2.4.25.
I find problems on setup tables of database.
The error is:

Database command failed:
CREATE TABLE IF NOT EXISTS TaskQueue (
TaskId INT NOT NULL AUTO_INCREMENT,
Callback MEDIUMTEXT DEFAULT NULL,
Parameters MEDIUMTEXT DEFAULT NULL,
Priority INT DEFAULT 3,
Description TEXT DEFAULT NULL,
INDEX (TaskId),
INDEX (Callback(64), Parameters(256))
);
(SQL error: Specified key was too long; max key length is 1000 bytes)

In MariaDB (and also in MySQL) now the default charset of a db is uft8mb4, the default engine is InnoDB and general speakong
charset is on uft8. In this situation the CREATE command of table 'TaskQueue' is invalid.
So, what do I need to do on MariaDB/MySQL config ?
Do I need to setup deafult to Engine=MyISAM anc charset=latin1 ?

Bye