Installing a clean ezp version in one of the mentioned versions generates the following error:

This Message if using php52
To synchronize your database with the distribution setup, run the following SQL commands:
DROP TABLE ezm_block;
DROP TABLE ezm_pool;

After upgrading to version to 4.5 and all of the ezflow extensions:

ALTER TABLE ezinfocollection ADD INDEX ezinfocollection_co_id_created ( contentobject_id, created );
ALTER TABLE ezkeyword_attribute_link ADD INDEX ezkeyword_attr_link_oaid ( objectattribute_id );
ALTER TABLE ezm_pool ADD INDEX ezm_pool_block_id_ts_hidden ( block_id, ts_hidden );
DROP TABLE ezstarrating;
DROP TABLE ezstarrating_data;
ALTER TABLE ezm_pool ADD INDEX ezm_pool_block_id_ts_hidden ( block_id, ts_hidden );

Steps to reproduce

1 . Install a clean 4.1.x or 4.2 version with ezflow
2 . Verify upgrade check tool messages for database consistence
3 . Upgrade using the ezupgrade tool
4 . Verify upgrade check tool messages for database consistence