this is all the notes I saw in addition to the changes on the announcement:

* The following adjustments, scheduled for patch 1.22, are in development and subject to change.
* The attributes of materia already existing in-game will automatically change to reflect the above following release of patch 1.22.
* In addition to the abovementioned fee, players must also provide a suitable catalyst.
* This method allows only the melding of the first piece of materia to any given item.