as described here

https://cursos.alura.com.br/forum/topico-montar-o-ambiente-para-utilizar-o-mysql-84273

migration fails:

cd /opt/jbpm-server-7.64.0/bin/  ; sudo ./jboss-cli.sh  --file=./jbpm-mysql-config.cli

as: 

mysql-connector-java-5.1.49.zip  →  mysql-connector-java-8.0.28.zip

                     <!--             <xa-datasource-class>com.mysql.jdbc.jdbc2.optional.MysqlXADataSource</xa-datasource-class> -->

                         <xa-datasource-class>com.mysql.cj.jdbc.MysqlXADataSource</xa-datasource-class>

I modified the driver in standalone.xml to   N.B. at 2 different line numbers 181 e 200 !!  : 

181  row about

 <xa-datasource-class>com.mysql.cj.jdbc.MysqlXADataSource</xa-datasource-class>

200 row about

<driver name="mysql" module="com.mysql">

    <driver-class>com.mysql.cj.jdbc.Driver</driver-class>

 <xa-datasource-class>com.mysql.cj.jdbc.MysqlXADataSource</xa-datasource-class>

</driver>

now is possible migration of from h2 a mysql