To upgrade from 1.1.0 to 1.2, run the upgrade_to_1.2.sql 
script in sql directory on the sphider database.

To upgrade from 1.2.3 to 1.2.5, run the upgrade_to_1.2.5.sql
script in sql directory on the sphider database.

To upgrade from 1.2.5 to 1.2.6, run the upgrade_to_1.2.6.sql
script in sql directory on the sphider database.